Sandbox for Proposed Challenges

Question

This "sandbox" is a place where Code Golf users can get feedback on prospective challenges they wish to post to main. This is useful because writing a clear and fully specified challenge on your first try can be difficult, and there is a much better chance of your challenge being well received if you post it in the sandbox first.

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Answer 1

Survival of the fittest king-of-the-hill

As Chris Jester-Young suggested here, i will propose my challenge here. At the moment, this is merely a draft but i want to ask for suggestions to this idea as early as possible.

For discussions, i suggest using the chatroom at chat.stackexchange.com specifically for this challenge.

My draft in its newest state plus all source code is hosted at github where you can make pull requests with suggestions.

---

The post here consists of the rules my challenge will have. Look at the github to see a lengthy explanation of what i post here. Feedback of all kind is appreciated!

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Rules

Board

The challenge is held on a two dimensional board with x and y coordinates. 0|0 is on the left-top side and increases in y downwards and in x to the right. Every field on the board can only hold one object. Objects are all kind of things in the game, from resources to units and even buildings. Board corners are solid, so the board is surrounded by walls. Everything on the board is randomly distributed. The board size is determined by the number of players in the game.

Actions

Every AI acts as one faction of humans. These factions have their explicit name and can be recognized by all other factions. Each round, all factions are given the complete board state and they have to submit some actions. Actions will be executed based on the time stamp of submission. So a faster calculating AI has the benefit of moving first. Animals and NPCs will move after all actions from the AIs are executed. Then there is a new round.

Game limits

The game ends, when there is only one faction left. There can be a time limit, if is turns out to take ages... There will also be a time limit for each round. Taking more time than the limit means, your program will be cut off and the rest of your actions will be omitted. After 5 consecutive rounds hitting the time limit, an AI will be disqualified.

Gameplay

Each faction starts the game with four workers and a stockpile. They have to collect wood, stone and food to survive. Food is used up every round to fill the workers stomach. All three resources will be needed to construct buildings and advance in technology and in numbers. Workers are able to reproduce in housings. but they can also be converted to soldiers. Soldiers can not work nor reproduce, but excel in their fighting ability. With more advanced technology, workers can be converted to better soldiers. Soldiers can not be upgraded.

Strategy

There are numerous buildings available and the more advanced cost a huge amount of resources. Fighters can destroy buildings, while workers can conquer them. Buildings allow for things like reproductions, boosts on resource collection and overall attributes of each unit. Units get more experienced in things, while they are doing them. This experience is handed down to the next generation. Since there need to be two units, to get an offspring, a genetic algorithm will mix their abilities together. This can be better or worse. Your units can have offspring with units from other factions, but both units have to agree on the matter. The offspring randomly chooses between the two factions and stays there.

Control

The AI does not control its units directly. It only gives orders. There is no limit on how many orders an AI can give each turn but every unit can only have one active order at a time. Giving a second order overrides the first one. Units try to execute the orders that are given to them. They are doing this automatically and orders are carried to the next round, if they are not fully completed. While the AI hat full informations over the board, their units have not. Giving an attack order to a place the unit can't see, the unit will try to walk there and attack when in view of the target.

Alliances

There is a global chat that all AIs share and where all AIs can talk to while calculating actions. AIs can specify other AIs that they think are friendly. They can not attack these. If two AIs each think of each other as friendly, they from a bond. A chain of such bonds is called an alliance. Even if you do not consider them friendly, your alliances friends are not attackable for you. So forming an alliance with someone, who friends everyone means, you cannot attack anyone, but they can attack you, if they don't friend back. Each round you can alter your friends to your liking. There is no such thing as an alliance chat, so you have to use encryption to chat in secret. And remember, in the end, only one AI wins the game.

Scoring

Scoring is done in number of rounds survived. Perhaps there will be some more scoring factors included to make the game more interesting.

---

Please bear in mind, that i will edit this answer a lot the next time to reflect the changes in the challenge.

Answer 2

Empire wars

This is very close to Risk, but not quite. You command an empire, composed of armies, trying to take over the world.

The world

The world is a grid. For n competitors, the side length of the grid is sqrt(n)*4 (casted to an integer). At the beginning, the world is part of the "neutral" empire. Each neutral army contains 200 soldiers. The neutral army only defends, it never attacks. Your starting army of your empire is randomly selected from the grid. Note that the world wraps around if you go off the edge.

Receiving soldiers

Every turn, you will be given 500 + 50t soldiers to distribute, where t is the number of armies/territories you command. You can give any amount to any army, as long as you don't exceed 500 + 50t in total.

You may then attack or transfer any number of soldiers to another location.

That means that, if you have enough soldiers, you can move soldiers from multiple different territories to multiple new territories.

Attack/Transfer

During your turn, you may move any number of soldiers from any of your armies to any of the squares bordering your army. You can move diagonally. One of two things will happen

1. You already control the square your army is moving to: Nothing special. The new square gets some more soldiers.

2. Another empire controls the square: The two armies will fight (see below). If your army wins, the surviving soldiers will inhabit the territory. Otherwise, any surviving soldiers will retreat back.

Battle

The order of battle is randomized every turn, because the empires who go first have a slight advantage or disadvantage (depends on the algorithm). For example, if I occupy a territory on my turn, but I go before another empire, then that empire could potentially attack my new territory.

Suppose a is the number of soldiers attacking and d is the number of soldiers defending. The defenders lose a * 0.6 soldiers and the attackers lose d * 0.7 soldiers. If the defenders have no soldiers remaining, the attacker's surviving soldiers inhabit the territory. For example, suppose the world looks like:

N-200 N-200 N-200 N-200
N-200 N-200 N-200 N-200
N-200 N-200 A-500 N-200
N-200 N-200 N-200 N-200

where N-200 represents a neutral army with 200 soldiers and A-500 represents an army of your empire. Suppose the following happens:

1. Your empire (A) decides to move 250 people north. First of all, north is not controlled by your empire, so a battle is started. N-200 loses 250 * 0.6 soldiers and A-500 loses 200 * 0.7 soldiers, with a result of N-200 --> 50 and the 250 attacking soldiers will be reduced to 110. Since the territory wasn't conquered, the 110 survivors retreat. The world will now look like:

   N-200 N-200 N-200 N-200
   N-200 N-200 N-50 N-200
   N-200 N-200 A-360 N-200
   N-200 N-200 N-200 N-200
   

2. You now decide to move 180 people north. The same thing happens: N-50 loses 108 soldiers and A-360 loses 35 soldiers. Since N-50 has been eliminated, the remaining 58 soldiers move into the new territory.

   N-200 N-200 N-200 N-200
   N-200 N-200 A-58 N-200
   N-200 N-200 A-180 N-200
   N-200 N-200 N-200 N-200
   

Note that neutral territories never attack.

Example implementation:

The code should be in Java (thinking of extending it to other languages) and needs to extend the abstract class Empire.

// The code MUST be in the package "empire" and extend the class "Empire" from mainengine
package empire;

import java.io.IOException;
import java.util.List;

import mainengine.*;

public class TestEmpire1 extends Empire {
    // Occurs at the beginning of the turn
    // You get 500 + 50t soldiers to deploy
    @Override
    public void deploy(ArmyDeployer toDeploy) {
        // Get all of my armies
        List<Army> armies = getArmies();
        // Distribute my new armies to each army evenly
        int perArmy = toDeploy.armiesLeft() / armies.size();
        for (Army a : armies) {
            a.addPower(toDeploy, perArmy);
        }
    }

    // You can move your armies as well
    @Override
    public void move() throws IOException {
        // Get the world
        World world = World.world;
        // Get the map of the world
        // Note that you can only see the areas adjacent to your armies
        // All other locations appear as "null"
        Army[][] map = getMap();
        for (Army a : getArmies()) {
            // Find the least guarded territory
            Move bestMove = null;
            int leastDefended = Integer.MAX_VALUE;
            for (Move move : Move.values()) {
                int newX = world.wrapPosition(move.getXOffset() + a.getPoint().x),
                    newY = world.wrapPosition(move.getYOffset() + a.getPoint().y);
                if (map[newY][newX] != null && map[newY][newX].getStrength() <= leastDefended) {
                    leastDefended = map[newY][newX].getStrength();
                    bestMove = move;
                }
            }
            // Attack with half of our strength
            a.move(bestMove, a.getStrength() / 2);
        }
    }

}

See github for the code that will be executing it: https://github.com/prakol16/EmpireWars/tree/master/EmpireWars/src

The "number of points" that an empire receives is how many territories it controls after one run (about 50, subject to change, or so turns). The program will be run 10 times and the empire with the most total points wins.

In addition, the program creates an html file record.html which contains a record of every turn.

Answer 3

XKCD: (Battle of the) Hats

http://imgs.xkcd.com/comics/hats.png

Enough background, get into the game

A king-of-the-hill challenge.

You all started at a point. At the count on 3, you decides to wear yourself 1 black hat, 2 black hats or 1 white hat.

Here's what happened: (If you find this description confusing, you can look at the table below, credit to Peter Taylor)

---

If you use 1 black hat ->

-> If your opponent also uses 1 black hat or white hat, your opponent moves backward 1 step.

-> If your opponent uses 2 black hats, you have 50% chance making your opponent moves 2 steps backward. Else your opponent does nothing.

---

If you use 2 black hats ->

-> If your opponent doesn't use white hat, your move is considered successful 2 black hats attempt. Your opponent moves backward x+3 steps, where x is # of your previous successful 2 black hats attempt.

-> Else: Your attack gives no effect.

---

If you use white hat ->

-> If your opponent use 2 black hat, you're considered making successful white hat attempt. Your opponent moves backward y+3 steps, where y is # of your previous successful white hat attempt.

-> Else: You're considered making a failed white hat attempt. You move backward z+3 steps, where z is # of your previous failed white hat attempt.

---

The game ends when somebody moves 20 step backward or 10 rounds played.

If one person moves 20 or more steps backward while one doesn't, then the one who not is declared the winner.

If both moves 20 or more steps backward in the same round or no one moves 20 or more steps backward in 10 rounds, no one win.

Your bot will play 5 tournaments. In each tournament, you face each enemy once. The player who score most win in those 5 tournaments accumulated, is declared the champion

Communication Protocol

Your bot will get this from STDIN:

id round step0 step1 move0 move 1

Where id is your player id, can be 0 or 1; round means current round (match starts at Round 1); step0 and step1 means how many step has player 0 and player 1 has taken; move0 and move1 is the move taken by player 0 and player 1.

In first round, move 0 and move 1 will be empty. In next round, it will the move as this

12w21

This means one player use 1 black hat; 2 black hats; white hat; 2 black hats; 1 black hat, respectively.

Your bot gives me output from your STDOUT as 1 if your bot want to wear 1 black hat, 2 if your bot want to wear 2 black hats, w if your bot want to wear white hat.

PS: Do aware that I use small-case "w"

---

Table:

                +--------------------+--------------------+---------------------+
                |                    |     P0 action      |                     |
                |         1          |         2          |          w          |
+---------------+--------------------+--------------------+---------------------+
|             1 | P0 back 1          | P0 back 0 or 2     | P0 back z0+4; z0++  |
|               | P1 back 1          | P1 back x0+3; x0++ | .                   |
+---------------+--------------------+--------------------+---------------------+
| P1 action   2 | P0 back x1+3; x1++ | P0 back x1+3; x1++ | .                   |
|               | P1 back 0 or 2     | P1 back x0+3; x0++ | P1 back y0+3; y0++  |
+---------------+--------------------+--------------------+---------------------+
|             w | .                  | P0 back y1+3; y1++ | P0 back z0+3; z0++  |
|               | P1 back z1+4; z1++ | .                  | P1 back z1+3; z1++  |
+---------------+--------------------+--------------------+---------------------+

Answer 4

Making a dichotomous key

A dichotomous key, also known as a single-access key is often used to identify plants/animals. Your task is, given a set of data, write the shortest program that outputs the shortest (in steps) possible dichotomous key. If there are multiple solutions, the program may print either one.

Input

Input will be received by stdin, or in cases where that doesn't exist (e.g. Client-side javascript) you can take input from prompt or something similar.

The input will be a list of items followed by characteristics: The format of the definition of an item will be

item[delimiter1]characteristic1[delimiter2]characteristic2[delimiter2]characteristic3

Your program may choose the delimiters. In this example, I will use : as delimiter one, and , as delimeter 2. Between each item definition is delimiter3, which will be \n in this example (but you can make it anything that isn't delimiter1 or delimiter2). Note that none of the delimeters can be [a-zA-Z] letters.

Characteristics and items are composed of a series of [a-zA-Z] characters.

Example input:

quadrilateral:fourSides
trapezoid:fourSides,onePairParallel
parallelogram:fourSides,twoPairsParallel,oppositeSidesEqual
rectangle:fourSides,twoPairsParallel,fourRightAngles,oppositeSidesEqual
rhombus:fourSides,twoPairsParallel,oppositeSidesEqual,allSidesEqual
square:fourSides,twoPairsParallel,oppositeSidesEqual,allSidesEqual,fourRightAngles

Output

Output should be written to stdout, or alert or something similar where it doesn't exist.

You must output a characteristic followed by delimiter one, followed by two integers separated by delimiter two. The first is the step to go to if the item contains the characteristic, and the second is the step to go to if the item doesn't contain the characteristic. Note that the 1st step is considered 0. Alternatively, instead of an integer, you could have an item.

Example output:

twoPairsParallel:2,1
onePairParallel:trapezoid,quadrilateral
allSidesEqual:3,4
fourRightAngles:square,rhombus
fourRightAngles:rectangle,parallelogram

This is code-golf so shortest code wins.

Answer 5

This is nearly done now, just need someone to double check that everything makes sense

Generate Lightning Forks in a 3D Grid

Objective:

Overview:
Write a program, that given the two inputs number of rays and ray length, will produce a procedurally random array of connected points, containing the ray number, number in sequence and coordinates of each point.

Details:
The lightning is in the form of rays, which are determined by points stored as coordinates in a grid.

The initial point (0,0,0), is the cloud, where the lightning is first generated. The first ray starts here and travels out in a random direction, and will continue moving in random directions (each point has an equal chance of any direction, not influenced by the previous point), and will terminate once it reaches the ray length limit or cannot go any further (if it fails enough new direction retries when intersecting with another point). This will leave a single path between the origin and the end point.

However, lighting doesn't stay as one single ray and will fork, so while all other rays should be generated in a similar way, their origin should be randomly chosen from any of the already generated points, and the sequence then continues from this point.

The Ray Number is simply which ray iteration the code is on. Each ray is it's own individual path. The origin point of the ray will have the same coordinates as the point it branches off from.

The Number In Sequence is how many points away from the cloud (or how far into the generation) it is. If lightning forks at point 50, both separate paths will start at 51. While this is not currently used for anything aside from checking the code is working correctly, it would allow for future improvements such as animation (see gif at bottom for an example).

Coordinates are the 3D points the ray passes through. They should be stored as integers.

Simple 2D Diagram:
Here is an example output during generation after 24 points have been calculated.
The numbers written in black are the numbers in sequence, and as you can see when the 2nd ray (blue) branches out, it continues from 10. The red line is an example of when it would try intersect with existing points and get stuck. This shows the cloud as it's own ray, you are free however to do this differently.

Rules:

• Can be written in any code (without extra plugins), although I can't guarantee anything but PHP and Python will be tested, unless someone else with access to a lot more languages helps out.
• Randomness must be seed based, so if you were to define a seed (not needed), it would produce the same result.
• A point can move in any one of the 3 dimensions - meaning it can go up, down, left, right, forwards, or backwards (x,y,z,-x,-y,-z) from the previous point, but not diagonally.
• No two points can have the same coordinates.
• The one exception of this rule is that each ray must start with the same coordinate of where it branches out (for the purpose of connecting everything together).
• If an intersection is detected, at least 3 retries must be done to find new direction, then it may be terminated. The retries must be for each point, so having 1 retry on 3 different points shouldn't terminate the ray.
• No multithreading allowed.
• The code should output the final number of points generated and time taken.
• The program should be timed to when the array of points is complete. Anything after this (such as for the bonus points) is fine and won't impact on the execution time.

Scoring:

• Generate 100 rays with a maximum length of 200. If your code is super efficient and you want to show off, you're welcome to post the times for more complex results.
  
• Most efficient code wins, based on the execution time. Someone will test multiple submissions and take an average from at least 4 generations to make it more fair.

Important: So I can easily check your code works as it should, I wrote something that will display the rays in a 3D program.
You'll need to generate 30 rays with a length of 15, in 2D (easy to switch - where it randomly chooses from from 6 directions, change this to 4), and copy it to pastebin. Format it like I have done here, and keep it limited to square brackets, commas, and integers: http://pastebin.com/8XHtv4is

Bonus Points:

• Given any two random points, there is one and only path between them both. If you can code something that would be able to calculate a path between these two random points and store it in a new array with the same structure, you get 15% off the execution time.

• Instead of limited to 3 dimensions, code it for n dimensions, as more than 3 dimensions should work, despite being a little hard to visualise. If you manage you can knock 10% from the execution time.

• As not everyone will be able to do it, this is only worth 5%, but you get it, if you code a way to visually draw the rays (2D is allowed, any method is allowed, but it must be able to run at the end of the code, as opposed to copying the list into a graphing program).

Tips:

• Start working with a 2D grid for easier debugging.
• Use small ray length and ray amount values until properly optimised.
• While intersections are fairly easy to see, diagonals are not, running the code with a single short ray to print the output can be useful.

Example code:

Generation Time for 100x200: 75-85 seconds

length=15
forks=30
import time
import random as rd
startTime=time.time()
def getDirection(num):
    if(num==1):
        direction=[1,0,0]
    if(num==2):
        direction=[-1,0,0]
    if(num==3):
        direction=[0,1,0]
    if(num==4):
        direction=[0,-1,0]
    if(num==5):
        direction=[0,0,1]
    if(num==6):
        direction=[0,0,-1]
    return direction
listOfPoints = [[0,[0,0,0],0]]
for i in range(forks):
    randomPoint = listOfPoints[rd.randint(0,len(listOfPoints)-1)]
    start = randomPoint[0]
    newLocation = randomPoint[1]
    listOfPoints.append([randomPoint[0],randomPoint[1],i+1])
    j=0
    j2=0
    while j in range(length):
        j+=1
        oldLocation = newLocation
        k = 0
        while True:
            invalid = 0
            newDirection = getDirection(rd.randint(1,6))
            newLocation = [oldLocation[0]+newDirection[0],oldLocation[1]+newDirection[1],oldLocation[2]+newDirection[2]]
            for n in range(len(listOfPoints)):
                location = listOfPoints[n][1]
                if location==newLocation:
                    invalid = 1
                    newLocation = oldLocation
            if invalid==0 or k>4:
                break
            k+=1
        if invalid == 0:
            listOfPoints.append([j2+start+1,newLocation,i+1])
            j2+=1

print "Time: "+str(round(time.time()-startTime,2))+" seconds"
print "Generated/Maximum points: "+str(len(listOfPoints))+"/"+str(length*forks)+"("+str(round(len(listOfPoints)/float(length*forks),3))+"%)"

Visualised Output:

(From a more advanced version I did before, I was aiming to make a flower)

Answer 6

Confused Automatons king-of-the-hill

[work in progress]

This is a 1v1 (or not? could be more) king-of-the-hill, where you and your opponent both issue commands to the same, perpetually confused, gladiators and try to survive.

Toroidal arena with N gladiators. They understand the following simple commands:

• Move one of 8 directions or
• Hold

plus one of:

• Shoot target. Range of 5. Can’t shoot the following turn.
• Dodge (no target required)
• Nothing

On each turn you may issue one command ([M/H]+[S/D/N]) to each gladiator. All gladiators will execute the commands from both players each turn. Movement happens first. If a gladiator is given two shoot commands, they will shoot twice that turn; two dodge commands and they will dodge twice. One dodge will avoid one shot. A gladiator can't shoot himself. Movement in opposite directions will cancel; movement in the same direction means moving a distance of two. If there is both an [H] command and an [M] command for the same gladiator, the [H] will be ignored.

One of the gladiators is your commander. You lose when your commander dies. Your commander ignores commands from your opponent. You don’t know which gladiator is your opponent’s commander.

Input

TBD

Output

TBD

Scoring

TBD

Answer 7

Unicode Case Mapping code-golf

Challenge:

Given a string as input, print it in both lowercase and uppercase.

The string will be valid UTF-8, and your output should be as well. Characters without lowercase or uppercase mappings should be printed unmodified. Invalid, un-assigned, and private-use characters need not be handled.

Uppercasing and lowercasing should be doing according to Unicode 7.0 "simple" case mapping rules.

Rules:

This is code-golf, shortest program wins. Your program shouldn't use any external data files or access anything from the internet; all of the information it needs should be contained within the code itself.

You may not use your language's built-in case-mapping functions, built-in copies of the Unicode Character Databse, or libraries such as ICU. For example, in Perl the lc and uc functions as well as Unicode::UCD are prohibited.

Since this challenge is about Unicode I will throw in a small scoring twist: if your program is valid Unicode text (in whatever encoding your language prefers, probably UTF-8) you may score it at a rate of one point per character (regardless of how many bytes those characters take up). If it contains binary data then it must be scored at one point per byte. I will clarify what constitutes "binary data" if I have to.

Bonus:

Support "full" Unicode case mapping. The difference between "full" and "simple" mapping is that in "simple" mapping every codepoint maps to a single codepoint, while in full mapping a codepoint may map to multiple codepoints. For example, the uppercase of the character "ff" (U+FB00) is "FF" (U+0046 U+0046). Assume that all "conditions" are false (that is, any rule with a non-empty condition_list should be ignored).

Question: offer a point bonus for this? Recognize a separate winner among people that manage it? Drop it entirely?

Resources:

• Unicode Standard Annex #44: Unicode Character Database — documentation for the UCD files.
• UnicodeData.txt — Unicode character properties, including simple lowercase/uppercase/titlecase mappings.
• SpecialCasing.txt — Special-case rules for casing: contains full mappings.

Answer 8

King of the server - virus wars

• There is a virtual machine with Linux running various services (SSH server, Apache (with SSL), FTP server, rsync server, etc);
• There is tool which checks that the server is running (periodically accessing all its services - trying to view the page from Apache, download a file from FTP server, etc.) and analysing responses for special ID codes;
• There are submissions that are started on the server as root and should "inject" some ID code (individual per solution) in as much as possible places while inhibiting competitors;
• Each solution should try to attain the following goals:
• • Make the server and it's services mention the ID code in maximum number of places with maximum reliability;
• • Avoid stopping the server or breaking any of the services, avoid breaking reboots;
• • Inhibiting competiting solutions (if any) while allowing them to post their ID code at least once;

The virtual machine gets booted, the solutions gets started there, then the script accesses the server from virtual network to check SSH/FTP/HTTP/... still running. The script also looks at the reply and counts any ID codes that appears in the replies. It happens multiple times. The serve gets rebooted N times.

Not all solutions gets planted on the server each time, just some random subset.

A solutions scheduled for the given round receive negative penalty points if:

1. The server crashed (stopped replying on requests from the virtual network);
2. Some service on the server crashed (i.e. SSH still works, but HTTP is down);
3. A competing solution have failed to provide it's ID code even once;

If your solution crashes something or fails to provice the code even once even if run alone (without competitors) - it gets disqualified.

The solutions may use variety of methods to complete the goals:

1. Just changing configuration in /etc;
2. Patching system libraries to inject the ID code and/or supress other solutions;
3. Carrying "clean" copy of libraries to avoid point "2.";
4. Loading kernel modules;
5. Extracting competing ID code and manually providing it exactly once (to avoid the "spawn camping" early-kill penalty);
6. Loading security modules to make root less omnipotent;
7. Overriding a boot loader, making the server boot nonstandardly...

The virtual machine image will be available from the beginning.

Questions:

1. Is the idea worth thinking and fits PPCG enough?
2. Shall all solutions be public from the beginning, or there can be hidden solutions (to prevent easy directed attacks)?
3. Shall binary-only submissions be allowed?

Answer 9

Dots and Boxes

The goal is writing a function in [language], that accepts the grid and outputs what dots it wants to connect next. This is a King of the Hill challenge.

How the game works

The (square) field has 6x6 dots. The two players are conenct one after another each time two neighbour dots (vertically or horizontally). If one player closed a square (1x1) in his last step, this square counts as his. The game is finished as soon there are no more dots to connect.

Scoring

Each program will be playing against each other program.

The score is the total number of conquered number of boxes.

Open Questions

• How can we encode the grid in an easy way as 2D(?) array?
• How should the function endcode which dots to connect?
• What language / environment would you suggest for doing so? (It would be easiest if there was only one language. I'd say Python or JavaScript.)
• Is it better to count the total of the captured squares or only the number of won matches?

Answer 10

Chad

king-of-the-hill chess

Chad is a variant of chess. It is played on an uncheckered board measuring twelve by twelve squares. Squares are denoted using standard chess notation, so a12 is the top left corner and l1 is the bottom right corner. The opening position of Chad looks like this:

Above: Chad gameboard and opening position.

The 3x3 area that the kings start in is called the castle. The twelve shaded squares around each castle is called the wall. Here are how the pieces interact with each other and the wall:

• The King can move and capture like a King but also as a Knight. However, he is confined to his 3x3 castle.
• The Rook moves like a Rook in chess, unimpeded by walls or castles. If the Rook ends on a square inside the enemy castle, it is automatically promoted into a Queen.
• A Queens move like a Queen in chess. She is also unimpeded by walls or castles.
• The mutual right of capture between two pieces (except for the King) exists if, and only if, one piece is on the enemy's wall, and the other piece is in their own castle. Otherwise, pieces simply block each other.
• The King may capture pieces inside his castle, provided he can attack the piece (remember that the King can move both as a King and as a Knight).
• Check occurs if the King is in the path of a Rook or Queen, regardless of whether the Rook or Queen is on the wall or not. Walls do not block checks.
• As in regular chess, white moves first, a capturing piece replaces the piece captured, and checkmate wins the game.
• A draw occurs if:
  • x moves have passed without any piece being captured.
  • There is three or less pieces on the board.
  • It is a stalemate.

This is a king-of-the-hill Chad competition. To enter write a program that decides what moves to make, using the IO format below. This program will be pitted against other entrants to find out which program is the strongest.

Inputs and Outputs

Your program will be ran from the command line for each move, and input will be given as a command line argument. Here is the input format:

[colour] [board] [history] [moves]

• [color] is 0 if you are playing White, and 1 if you are playing Black.

• [board] is an ASCII representation of the board with newlines stripped. K is a King, R is a Rook. Lowercase letters indicate black, uppercase means white. A dot . is a blank space. The starting position would look like this:

   ...............................rrr.........rkr.........rrr................RRR.........RKR.........RRR...............................  
  

• [history] is a comma separated list of the moves you and your oppoment have done. It is in a modified long algebraic notation, consisting of the starting and ending squares separated by a hyphen, without a letter identifer for the piece. If it is a capture, the hyphen is replaced with an x. There is no !? or other such ornaments. This is blank if you are White and making the first move - be prepared for this!

• [moves] is a comma separated list of the valid moves you can make in your current situation. It is also in the modified long algebraic notation.

Note that you don't have to use all of the information given in the input if you do not want to. The information is supplied to simplify the process of making the program.

You program should output a single move in the modified long algebraic notation, indicating what move you want to make on that turn. The move must be valid. The program must output its move within y seconds, otherwise it will resign. If the program outputs anything other than a valid move, it will be counted as a resignation.

Entering

To enter, submit an answer with the following information:

• The name of the bot (to be used for score tables, etc.)
• The language the bot is written in
• The command line command needed to run the bot

If I cannot include your bot for any reason, I will add a comment explaining why I cannot. I will endeavour to install any programs required to run your bot, as long as it is legally free to access (sorry Mathematica people).

The final round will occur on xxxx/xx/xx. It is a round robin. Each bot plays against each other bot two times - once as black, and once as white. If a bot wins both rounds, it gains 1 point. If it wins one round, it gains 0.5 points. If it doesn't win either, it gains 0 points. The bot with the most points gets the green checkmark.

I will also hold regular practice rounds, of which you may find the results of here. The last practice round was held on xxxx/xx/xx. These practice rounds will continue even after the final round has finished.

Questions

• Is the explanation of Chad's rules clear?
• What would be good values for x and y?
• Would the extra information in the input be helpful?
• Any other advice would be appreciated.

I haven't written the control program yet. I intend on getting the specification ironed out first.

Answer 11

King of the Tournaments

This game is based off of Graph Theory Tournaments

The competition will be a series of tournaments, where the Kings of a tournament will play in the next until the winner(s) is found

Every player will play every other player exactly once in a tournament. Each player will recieve 5*N points each tournament (where N is the number of opponents in that tournament). Furthermore, each player will have an advantage over N/2 players, and a disadvantage to N/2 players. This advantage is decided at the beginning of the game.

Each battle will consist of a player commiting X points. Whoever commits more points will win that battle. If both players commit the same amount of points, the player with the advantage over the other will win.

After a tournament, the Kings will be the players that defeat all other players. P1 defeats P2 if P1 beat P2 in battle, or if P1 beat a player that beat P2. If all players are kings, then the players with the least amounts of wins this tournament are eliminated. If all have the same amount of wins, then the players with the least amount of total wins are eliminated. In the case of a tie, the remaining players are declared the winners

IO

Your bot must stay alive throughout the entire game. You will pass in a number every round through STDOUT. You may pass in a few codes through STDOUT to recieve information via STDIN:

W will return IDs of the players you have won to this tournament

L will return the IDs of the players you have lost to this tournament

OW will return the IDs of the players your opponent has won this tournament

OL will return the IDs of the players your opponent has lost to this tournament

A will return 1 if you have an advantage over the player, else 0

H will return the history of your battles against the player. The list will be comma-seperated, where each battle is represented by Num1/Num2 where Num1 is the points you committed, and Num2 is the points your opponent committed.

Answer 12

Thinking about the Box outside of the Box

(looking for input from community)

Everyone has heard about the 9 points 4 lines challenge, where the goal is to connect all the points on a 3x3 grid with only 4 straight line segments, and without lifting your pen.

It has been proven that it is simple to calculate the minimum number of lines needed for any square:

Write a program that takes 2 positive integers as inputs, the dimensions of the grid of points (x points wide, y points tall) and calculates the minimum number of straight consecutive line segments needed to join all of the points on the grid.

The line segments may go off of the grid of points. (obviously :P) If either input is 0, output 0. If either input is 1, output 1. Otherwise you have to calculate the result. The inputs can be any positive integer, so hardcoding the solution is impossible.

Your program is correct until proven wrong. Only one counterexample on one set of dimensions is enough to prove a program wrong. (lets say a program outputs 5 for the set x=3, y=3, and the real solution is 4, then the entire program is wrong and it is not counted)

This is a code-golf challenge, shortest code to fulfill the requirements wins.

Answer 13

Pointlessly Restrictive Integers

[COMPLETE. Currently proofreading. Waiting for upvotes / objections before posting.]

In this question, all code blocks are independent of each other.

I'm designing a new programming language called Pointlessly Restrictive. The integers in Pointlessly Restrictive work in a peculiar fashion:

1. An integer must be explicitly declared with its length before being used (there is one exception to this rule, described below). This is done using the syntax A = [x], where A is the name of the integer (always a single, uppercase character) and x is the length of the integer. For instance:

   A = [2]
   B = [5]
   

   This declares an integer A of length 2, and an integer B of length 5. Note that at this point, the actual digits of the integer are not defined - so any integer of the specified length is a possible value. For example:

   A = 23
   

   is an invalid statement, because I haven't declared the variable with its length before using it.

2. The length of an integer is immutable. For instance:

   A = [5]
   A = [3]
   

   is invalid, because I cannot change the length of an integer after making it.

3. Values are assigned to an integer using the syntax B = x. For instance:

   B = [5]
   B = 21436
   

   is a valid assignment. Note that:

   B = [5]
   B = 314
   

   would be invalid, because the values given is inconsistent with the specified length of 5.

4. The + operator only concatenates integers, as if they were strings. For instance:

   A = [3]
   A = 123
   B = [2]
   B = 45
   C = A + B
   

   C, in this case, is equal to 12345. Note that I didn't need to declare the length of C before using it – the length is instead decided based on the component integers. In addition, I can use the [x] notation in this definition method:

   A = [3]
   A = 123
   C = A + [2]
   

   Any integer that has length 5 and begins with 123 is a possible value for C. In addition, if I use an integer twice in this definition method, it must hold the same value each time:

   A = [2]
   C = A + A + A
   D = C + [2]
   

   Any integer that consists of a subsequence of length 2 repeated three times (for instance, 161616) is a possible value for C. That possible value, with any two numbers after it, would be a possible value for D (e.g. 16161623). For instance, the sequence 142632 could not be C.

5. A value is printed by baldly printing the name of the integer on one line. If there are unknown digits, it substitutes lower case letters - the letters that are chosen are up to the interpreter. If there are more than 26 lower case letters required (e.g. A = [27]), it is an error.

   A = [2]
   A = 14
   A
   

   outputs 14. Another example:

   A = [3]
   A = 163
   B = A + [1]
   B
   

   outputs 163a.

   A = [3]
   B = A + A + [1]
   B
   

   outputs abcabcde

   Note that the abc repeats because the A repeats.

6. Integers can be reassigned, specialised, or generalised at any time. For instance:

   A = [2]
   A = 13
   B = A + [1]
   

   B is equal to 13a. This is also possible:

   A = [2]
   A = 13
   B = A + [1]
   B = 134
   

   On the fourth line, I have specialised B to a specific value. This is also possible:

   A = [2]
   A = 13
   B = A + 1
   B = [3]
   

   On the fourth line, I have generalised B to make it less specific. However, note that I cannot change the length of the integer - so B = [4] there would have been invalid.

Pointlessly Restrictive requires each statement to be on its own line. There is no semicolons at the end of lines.

Your task is to write an interpreter for Pointlessly Restrictive. It should be runnable from the command line - as its input, it will be given a filename, which can be assumed to be in the working directory of the operating system. The file contains some Pointlessly Restrictive statements. Your interpreter should check for any errors in the file (for instance, an assignment with the incorrect length), and output Error! if there is an error.

If there are no errors in the file, output whatever values are printed in the file.

Sample Inputs and Outputs

Input:

A = [2]
A = 13
A

Output:

13

Input:

A = [2]
A = 13
B = A + A
B

Output:

1313

Input:

C = [4] + [2] + [3]
C

Output:

abcdefghi

Input:

J = [2]
J = 13
L = [4]
L = 143 + [1]
K = L + J
K

Output:

143a13

Input:

J = [2]
K = J + J + J
K = 231323
K

Output:

Error!

Input:

J = [2]
K = J + J + J
L = K + [3]
K
L

Output:

abababcde

Notes

• Spaces do not hold any syntactic value in Pointlessly Restrictive - A = [2] is equivalent to A=[2], A= [2], or even A=[ 2 ].
• This means that the integer 123 54 is the same thing as 12354 for your interpreter.

Answer 14

Markdown to HTML converter

Challenge

Write a program that takes a file name ending in .md, .mkd or .markdown as a command-line argument (or the closest equivalent in your language of choice) and converts it to a valid HTML 5 document.

Rules

• If an error is detected, you must print an error message and terminate the program with a non-zero exit status.
• The output file name must be the input file name with the extension changed to .html.
• You don't have to include a doctype or <html>, <head>, <body> tags.
• You must support everything listed in the CommonMark specification, except for embedded HTML and HTML entities.
• You may not use an existing library or similar tool for processing Markdown.

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code-golf

Answer 15

Play Your Cards Right

code-golf

Game Rules

Play your card right is a game played with a pack of 52 cards (no jokers). At the start the deck is shuffled and the dealer will lay a single card on the table. The player then has to decide if the next card is higher or lower than the card on the table (note that ace is low here).

The dealer then lays another card on the table. If the card is the same as your guess (higher or lower), then you continue the game. If the card is equal to the last or not the same as your guess, all of the cards on the table are put into a separate pile and the game starts again (the cards in the separate pile are completely discounted).

You lose the game when the deck is emptied. You win the game if you get six cards on the table.

Challenge

Given the last card to be laid on the table you must make a guess as to whether the next card will be higher or lower.

Specifics

The necessary information will be supplied via argv:

• If the argument is newGame then wipe all data stored about the previous game
• If the argument is clearTable then clear the table and move all cards to the separate pile
• If the argument is not detailed above then it is a card name: 1 to 10 or J,Q,K,A

You may store information. I will be testing this on Ubuntu 12.04.

Winning

The shortest code wins. Please note that these have to be optimal solutions (winning most of the games played by the following controller)

Controller coming tomorrow (8/10)

Answer 16

I posted this earlier but they suggested I put it in the sandbox which made a lot of sense.

Reading sheet music

Your job is to take an image of sheet music and make it usefull for someone that doesn't read notes.

Output

3/4 (Which is the beat)
C F B,A,D E F C (Notes, Space seperated and comma seperated if notes are tied)
Images of the notes to play.

Layout images: The images must show a piano with the layout of an 61 key piano.

Each image will display a set of 5 consecutive notes. Tied notes will be treated as 1 note.
If the first note of a set is C there will be a '1' on the C key,
Second note F there will be a '2' on the F key and so on.
Like i said tied notes will be treated as 1 note but the index will count up.
So B,A,D will result in:
'1' on B; '2' on A; '3' on D.

If the same note is used twice in 1 set the note will show both indexes. How you display that is up to you, you can either seperate them by comma or newline.

Some information on reading notes can be found here:
http://www.wikihow.com/Read-Music
http://readsheetmusic.info/readingmusic.shtml

Submitted answers must have:

• The code (Golfed and ungolfed).
• Image used (or link to image).
• The output (both text and images).

Not sure about the tag. I tagged it code-golf for now but if someone has a better idea let me know.
(should I also use the kolmogorov-complexity tag?)

Right now this is code-golf so the one with the lowest bytes wins.

Happy coding :)

Answer 17

5 Miscellaneous Flag Challenges code-golf graphical-output geometry

We've had questions on the South Korean flag and the flag of Nepal. I thought that some other flag questions could be interesting.

I've grouped these into one post to avoid cluttering the sandbox with potentially bad posts. Once we've decided which of these are worth doing challenges for, I'll separate them out into separate posts, and make exact specifications of what it should look like.

Flag pictures taken from CIA World Factbook, which is in the public domain.

How much hardcoding should be allowed, if any? Is it better to decide on a per-flag basis?

Your task is to output the flag, to a file, STDOUT or the screen, in any common format (SVG, PostScript, RAW, PNG).

Malawi

Pros: Relatively simple
Cons: The "beams of sunlight" may need to be simplified slightly as they are some weird shape that I don't even know a name for

Saint Pierre and Miquelon

Pros: Quite a lot of repetition. Complex but not impossible. Probably fun.
Cons: That ship and the lions are going to be quite difficult - probably need to be simplified a bit

Australia

Pros: Simple geometric shapes. There's nothing hugely overcomplicated here. Some repetition. Shouldn't be too hard.
Cons: The stars have already appeared in the Nepal question - there is some overlap.

Mongolia

Pros: Simple geometric shapes (mostly), but quite a lot of them.
Cons: The yin-yang bit is similar to the South Korean flag, which we've done already

Togo

Pros: Simple
Cons: Maybe too simple?

Answer 18

Rearrange pixels from one image to form another, with different pixel counts

This would be very similar to American Gothic in the palette of Mona Lisa: Rearrange the pixels except that the images would not necessarily have the same area. If the palette image is larger, then the pixels can be chosen amongst and some left unused. If the palette image is smaller, then the result will be resized/resampled to the same aspect ratio as the other image.

The inspiration for this challenge is a real world application, using limited numbers of colored tiles to make a mosaic copy of a full color image. There would be an unlimited number of white/background tiles, but I can't think of a way to represent that in the challenge description, so I'd probably just fake the number of white tiles for a given target resolution.

Answer 19

Draw the Tree of Life

A codegolf contest to render the tree of life data (which is in the simple Newick format) sideways in ASCII, using the same formatting as this example:

   __/a
__/  \b
  \   _/c
   \_/ \d
     \e

Note that the distance in the source data is ignored; the tree should be drawn as compact as possible.

The source data can be fed into the program via stdin or by opening a file or as a parameter to a function. The output should be printing to stdout.

The output should not be hard-coded; the tree data must be read in and parsed by the program.

Actually printing a tree on its side is itself a bit of a coding challenge; see this SO question for inspiration.

Answer 20

Multi-File Code Golf

This is a new challenge Idea. Multi-File Code Golf. The idea is to write your golfed code in more than one file, and your score is the size of the largest file.

Your Program

You need to fit the specs with a program that spans multiple files. Any languages that use multiple files are valid. For example you could use C++ with a header file, JS/HTML or Ruby with require. files may be named anything you want, and be in any directory.

Score equal to the size of your largest file. (in bytes)

Chalinge

(Originally I had tic-tac-toe, but I decided that was a bad idea.) I need a good idea for a challenge that will work well in this format. Any ideas? It needs to be complex enough for multiple files to be helpful.

Answer 21

Help me sweep the floors

I have to sweep the floor of an MxN foot floor every night, where M and N can be any value between 1 and 1000. I need to know the most efficient method of sweeping this floor so I can get it done in the least amount of time.

Rules:

1. Each stroke of the broom clears a 1 square foot area.
2. Each stroke of the broom can be directed in one of 4 directions - North, South, East, or West. You can represent these as N, S, E, and W, respectively.
3. When I make a stroke, if there is more than 1 unit of dirt on a square, 75% of the dirt will go onto the square directly swept towards, and the remaining 25% will be equally divided among the side squares. If there is less than 1 unit of dirt, 90% of the dirt will go onto to square swept towards, and the remaining 10% is divided among the side squares. The back square receives no dirt. If I sweep into the wall, 75% of the dirt remains on the swept square. If I sweep adjacent to the wall, there is only one side square.
4. Your program must keep track of the strokes I need to sweep each floor - this is your score.
5. I must stand in a square adjacent to the square I am sweeping. I can sweep that square in any direction, but I 95% of the time I will sweep to my right or left; otherwise, I brush the dirt into the air and choke or sweep it all over my feet.
6. Each square initially contains 1 unit of dirt. The floor is considered clean when no square has more than .025 units of dirt remaining on it.
7. When I take a step, I can either step onto an adjacent square or over an adjacent square onto the next square.
8. The floor is considered swept when the remaining dirt is contained in one square on the floor so I can pick it up.
9. I start at any position [0, {0-N}]. Your program must input a value in the range of 0-N on which I start.

Your program must return the minimum number of steps and strokes I take to sweep this floor. It may not backtrack and do some steps over, but it can use look-ahead - it must simulate sweeping the floor in actual life. It must take as input M and N, as well as a value in the range of 0-N specifying where the door is, and output to the screen how many strokes I must take to sweep the floor. Your score is the number of strokes I must take. The program that returns the lowest number of strokes for any input is the winner. Ties will be won by the smallest program character-wise. Your program will be disqualified if you do not explain the algorithm used in the answer.

code-challenge code-golf

Answer 22

md5sum Creator

This is my first code golf challenge; critiquing welcome.

Your task is to create a new md5sum function. You need to output to STDOUT the input, a space or a tab character, the md5sum, then a new line. The spec for an md5sum can be found here, thanks to the IETF. For example:

1 c4ca4238a0b923820dcc509a6f75849b
2 c81e728d9d4c2f636f067f89cc14862c
... 
//hashes generated on http://www.md5.cz/

• You may use existing libraries so long as you are not directly calling an md5sum function from within that library.
• Output is not case sensitive (A is the same as a when it comes to an md5sum).
• Your program/function will take in a string, and output the md5sum as a string
• No downloading data from the Internet.
• Code Golf, so the shortest answer wins!

Answer 23

Traders for life

In this game, each bot will own a factory that accepts N products, and can produce M of a different product, denoted by #,Input->#,Output. There are 3 products A,B, and C and three types of factories, A->B, B->C, and C->A. Each factory of the same type will input the same number of products, and outputs the same number of products. Each both will be assigned a factory type, which can be queried (as described below) Producing A->B->C->A will increase the total amount of A.

Example: Bot 1's factory is 5A->2B, and starts with 500A. Bot 2's factory is 3B->7C and starts with 300B. Bot 3's factory is 5C->6A and starts with 500C.

You start with $1000, and your goal is to increase that money. Each turn you will produce, buy, and then sell in that order.

To produce you will pass in the number of inputs. If you pass in more inputs than you currently have in inventory, then you will only produce what you have in inventory. If the amount input isn't divisible, then a remainder of your input will remain which couldn't be produced.

To sell, you will pass the type you want to sell, the price, and the max amount you will sell. To buy, you will pass the type you want to buy, the max you will pay for it, and the max amount you will buy. The buyer with the highest max price will then be paired up with the seller with the highest price that is under the buyer's price. The buyer will then buy as many products as possible at the seller's price. If the seller reaches his maximum of products to sell, then the buyer will continue to buy from the next seller. If the buyer reaches his maximum of products to buy, then the seller will continue to sell his product to the buyer with the next highest maximum price.

All products and dollar amounts are integers (there are no cents or partial products).

There will be 3 copies of each bot, each assigned to a different factory. These bots cannot communicate with each other or with any other bot.

The player with the most money across all of their bots after 500 rounds wins.

Any language can be used, and input/output will come through STDIO. If you wanted to produce 34 of your product, buy 10 of product A at the price $5 and sell 20 of product B at the price of $6, then you would pass in P,34 B,A,10,5 S,B,20,6.

At any time you can pass in:

I to query your inventory, which will return something like 5A 10B 8C

M to query the amount of money you have

T to query your history of trades. It will be a space delimited list of trades. Each trade will look like like B,1275,A,49,90 (You bought from player #1275 49 of product A at the price of $90) or S,385,B,29,30 (You sold to player #385 29 of product B at the price of $30).

R to query the number of rounds left

F to query your factory type. It will return something like 5A->2B

Answer 24

Smuggle these Pincodes

After many years, our covert agent has managed to amass a list of all PIN codes in an enemy nation.

But there is a complication. The government of the country did become aware of our actions. Now our agent needs to smuggle the PINs past the customs without being caught!

Our spy needs help. Hiding a list of 10 000 codes will be too difficult. Luckily, our government can enlist the help of its loyal programmers (you!).

The Challenge

Write a program that will output a list of all PIN codes from 0000 up to 9999 (inclusive). The program needs to be as short as possible to get past customs unnoticed.

Rules

• The PINs must each be on a separate line.
• The program may not output anything other than the required output. However, it may output one (and no more than one) line end after the last PIN; e.g. 9999\n.

And, in case you were wondering:

• Your program must not:
  • Depend on any external resources.
  • Depend on having a specific file name.
  • Take exceptionally long to run. If your program runs over a minute on an average home user’s computer, it’s invalid.
  • Be written in a programming language for which there did not exist a publicly available compiler / interpreter before this challenge was posted.

An example of the correct output can be seen here.

Scoring

The shortest code (in bytes, in any language) wins.

Any non-standard command-line arguments (arguments that aren’t normally required to run a script) count towards the total character count.

Your program’s output may deviate from the given list order, in which case your program’s byte count will incur a +10% penalty (rounded up).

Answer 25

Writing the Hydra Function

restricted-source optimization

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Preamble

Sometime in the early 21st century, computer scientists would discover the Hydra function (also known as the Lächerlich function), f, whose signature is given by

R = f( A, B, L, x, y, z )

where A, B, L, and R are finite integers, and x, y, and z are integers in the range [-2³¹  2³¹).

The function would quickly rise to preeminence due to the fact that it can perform 40 useful and well-known binary operations on A and B, returning the result in R. These operations are listed in the section "Operations" below, which provides a rigorous description of each.

It is important to note here that "integer" refers to the mathematical concept of an integer. In particular, there is no concept of integer overflow or of binary representation. In the case of variables A, B, and L, integer values are unbounded. In the case of x, y, z, the variables may not violate their explicit bound; any operation that could potentially assign an out-of-range value to these variables is an error and forbidden.

Operations

The following code snippet defines all 40 (potential) operations of f. In each case, a name, description, and precise mathematical definition is provided. As a convenience, each operation also includes a C function that (notwithstanding data type bounds) implements the operation when compiled by gcc. In all cases, the mathematical definition should be considered authoritative.

<style>tr:nth-child(4n-3) td:first-child { width: 150px; font: bold 24px Times New Roman,Times,serif; }</style><style>tr:nth-child(4n-2) span { font-family: Courier New,monospace; }</style><style>tr:nth-child(4n) { font-family: Courier New,monospace; white-space:pre; }</style><style>tr:nth-child(4n) td { padding-bottom: 50px; }</style><script type="text/javascript" src="http://code.jquery.com/jquery-1.10.1.min.js"></script><div>Note that \(\left\lfloor\frac{A}{B}\right\rfloor _0\) indicates "divide and truncate towards zero", and that \(\operatorname{sgn}\left( x\right)\) indicates the signum function evaluated at \(x\).<br><br>Also note that for operations conditionally returning \({\rm anything}\), "anything" may be any value representable as an integer, or a fatal error. "Anything" does not have to be consistent from operation to operation. You may rely on the results returned for "anything" in subsequent calculations.</div><hr><br><br><div id="main">1. 0 [Constant 0] (0) \[R = 0\cdot A + 0\cdot B\] {{return 0;}} 2. 1 [Constant 1] (1) \[R = 1 + 0\cdot A + 0\cdot B\] {{return 1;}} 3. 2 [Constant 2] (2) \[R = 2 + 0\cdot A + 0\cdot B\] {{return 2;}} 4. A [Value of A] (A) \[R = A + 0\cdot B\] {{return A;}} 5. A + B [Sum of A and B] (sum) \[R = A + B\] {{return A + B;}} 6. A - B [Difference of A and B] (diff) \[R = A - B\] {{return A - B;}} 7. AB [Product of A and B] (prod) \[R = AB\] {{return A*B;}} 8. A &#247; B [Truncated Quotient of A by B] (div) \[R = \left\{ {\begin{array}{*{20}{l}}!!{\rm{anything}}&{{\rm{if\ }}B = 0} \\!!{\left\lfloor {\frac{A}{B}} \right\rfloor _0}&{{\rm{otherwise}}}!!\end{array}} \right.\] {{return A/B;}} 9. A &#247; B Remainder [Remainder after Division of A by B] (rem) \[R = \left\{ {\begin{array}{*{20}{l}}!!{\rm{anything}}&{{\rm{if\ }}B = 0} \\!!{A - B\left\lfloor {\frac{A}{B}} \right\rfloor _0}&{{\rm{otherwise}}}!!\end{array}} \right.\] {{return A % B;}} 10. A modulo |B| [A Modulo |B|] (mod) \[R = \left\{ {\begin{array}{*{20}{l}}!!{\rm{anything}}&{{\rm{if\ }}B = 0} \\!!{A\operatorname{mod} \left| B\right|}&{{\rm{otherwise}}}!!\end{array}} \right.\] {{   int X, Q;!!   X = B < 0 ? -B : B;!!   Q = A % X;!!   return Q < 0 ? Q + X : Q;}} 11. A = B [A Equals B] (is) \[R = \left\{ {\begin{array}{*{20}{l}}!!{1}&{{\rm{if\ }}A = B} \\!!{0}&{{\rm{otherwise}}}!!\end{array}} \right.\] {{return A == B;}} 12. |A| > |B| [A is of Greater Magnitude than B] (gmag) \[R = \left\{ {\begin{array}{*{20}{l}}!!{1}&{{\rm{if\ }}\left| A\right| > \left| B\right|} \\!!{0}&{{\rm{otherwise}}}!!\end{array}} \right.\] {{return (A > 0 ? A : -A) > (B > 0 ? B : -B);}} 13. A &and; B [Both A and B are Nonzero] (and) \[R = \left\{ {\begin{array}{*{20}{l}}!!{1}&{{\rm{if\ }}\left( A \neq 0\right) \wedge \left( B \neq 0\right)} \\!!{0}&{{\rm{otherwise}}}!!\end{array}} \right.\] {{return A && B;}} 14. A &or; B [Either A or B is Nonzero] (or) \[R = \left\{ {\begin{array}{*{20}{l}}!!{1}&{{\rm{if\ }}\left( A \neq 0\right) \vee \left( B \neq 0\right)} \\!!{0}&{{\rm{otherwise}}}!!\end{array}} \right.\] {{return A || B;}} 15. A &#8891; B [Either A or B is Nonzero, but Not Both] (xor) \[R = \left\{ {\begin{array}{*{20}{l}}!!{1}&{{\rm{if\ }}\left( A \neq 0\right) \wedge \left( B = 0\right)} \\!!{1}&{{\rm{if\ }}\left( A = 0\right) \wedge \left( B \neq 0\right)} \\!!{0}&{{\rm{otherwise}}}!!\end{array}} \right.\] {{return (A != 0) ^ (B != 0);}} 16. A<sup>B</sup> [A to the Power of B] (pow) \[R = \left\{ {\begin{array}{*{20}{l}}!!{A^B}&{{\rm{if\ }}B \geq 0\rm{\ or\ }\left| A\right| = 1} \\!!{0}&{{\rm{otherwise}}}!!\end{array}} \right.\] {{return (int)pow( A, B );}} 17. &#189;(A + B) [Average (Arithmetic Mean) of A and B] (avg) \[R = \left\lfloor\frac{A + B}{2}\right\rfloor _0\] {{return (A + B)/2;}} 18. A<sup>2</sup> + B<sup>2</sup> [Sum of Squares of A and B] (sumsqs) \[R = A^2 + B^2\] {{return A*A + B*B;}} 19. A<sup>2</sup> - B<sup>2</sup> [Difference of Squares of A and B] (diffsqs) \[R = A^2 - B^2\] {{return A*A - B*B;}} 20. &#189;((-1)<sup>A</sup> - (-1)<sup>B</sup>) [Synchronicity of A and B] (sync) \[R = \left( -1\right)^A - \left( -1\right)^B\] {{return (int)(pow( -1, A ) - pow( -1, B ));}} 21. |A + B| [Absolute Sum of A and B] (abssum) \[R = \left| A + B\right|\] {{return A + B < 0 ? -(A + B) : (A + B);}} 22. |A - B| [Distance from A to B] (dist) \[R = \left| A - B\right|\] {{return A < B ? (B - A) : (A - B);}} 23. max( A, B ) [Maximum of A and B] (max) \[R = \max\left( A, B\right)\] {{return A > B ? A : B;}} 24. min( A, B ) [Minimum of A and B] (min) \[R = \min\left( A, B\right)\] {{return A < B ? A : B;}} 25. minmod( A, B ) [Minmod Limiter] (minmod) \[R = \left\{ {\begin{array}{*{20}{l}}!!{\min\left( A, B\right)}&{{\rm{if\ }}A > 0 {\rm\ and\ } B > 0} \\!!{\max\left( A, B\right)}&{{\rm{if\ }}A < 0 {\rm\ and\ } B < 0} \\!!{0}&{{\rm{otherwise}}}!!\end{array}} \right.\] {{   if( A > 0 && B > 0 )!!      return A < B ? A : B;!!   if( A < 0 && B < 0 )!!      return A > B ? A : B;!!   return 0;}} 26. A ? B : 0 [Return B Conditionally] (condb) \[R = \left\{ {\begin{array}{*{20}{l}}!!{B}&{{\rm{if\ }}A \neq 0} \\!!{0}&{{\rm{otherwise}}}!!\end{array}} \right.\] {{return A ? B : 0;}} 27. &#189;(A + B)(|B - A| + 1) [Sum of Integers from A to B] (sumatob) \[R = \frac{\left( A + B\right)\left( \left| B - A\right| + 1\right)}{2}\] {{return (A + B)*((B < A ? (A - B) : (B - A)) + 1)/2;}} 28. A <<<sub>2</sub> B [Left-shift A by B Zeroes in Binary] (rsh) \[R = \left\{ {\begin{array}{*{20}{l}}!!{2^B A}&{{\rm{if\ }}B \geq 0} \\!!{\left\lfloor\frac{A}{2^{-B}}\right\rfloor _0}&{{\rm{otherwise}}}!!\end{array}} \right.\] {{return B >= 0 ? A*(1 << B) : A/(1 << -B);}} 29. A <<<sub>10</sub> B [Left-shift A by B Zeroes in Decimal] (rsh10) \[R = \left\{ {\begin{array}{*{20}{l}}!!{10^B A}&{{\rm{if\ }}B \geq 0} \\!!{\left\lfloor\frac{A}{10^{-B}} \right\rfloor _0}&{{\rm{otherwise}}}!!\end{array}} \right.\] {{return (int)A*pow( 10, B );}} 30. A + sgn(B - A) [Increment A Towards B] (twrdb) \[R = A + \operatorname{sgn}\left( B - A \right)\] {{return A + (B > A) - (B < A);}} 31. |A| sgn(B) [Magnitude of A with the Phase of B] (magphs) \[R = \left| A\right|\operatorname{sgn}\left( B\right)\] {{return (A < 0 ? -A : A)*((B > 0) - (B < 0));}} 32. |A| > |B| ? A : B [Return Furthest From Zero: A or B] (ffzero) \[R = \left\{ {\begin{array}{*{20}{l}}!! {A\rm{\ or\ }B}&{{\rm{if\ }}\left| A\right| = \left| B\right|} \\!!{A}&{{\rm{if\ }}\left| A\right| > \left| B\right|} \\!!{B}&{{\rm{otherwise}}}!!\end{array}} \right.\] {{return (A < 0 ? -A : A) > (B < 0 ? -B : B) ? A : B;}} 33. gcd( |A|, |B| ) [Greatest Common Denominator of A and B] (gcd) \[R = \left\{ {\begin{array}{*{20}{l}}!!{\rm{anything}}&{{\rm{if\ }}A = 0\rm{\ or\ }B = 0} \\!!{\operatorname{gcd}\left( {\left| A\right| , \left| B\right|}\right)}&{{\rm{otherwise}}}!!\end{array}} \right.\] {{   int X, Y, T;!!   X = A < 0 ? -A : A;!!   Y = B < 0 ? -B : B;!!   while( Y != 0 ) {!!      T = Y;!!      Y = X % Y;!!      X := T;!!   }!!   return X;}} 34. lcm( |A|, |B| ) [Least Common Multiple of A and B] (lcm) \[R = \left\{ {\begin{array}{*{20}{l}}!!{\rm{anything}}&{{\rm{if\ }}A = 0\rm{\ or\ }B = 0} \\!!{\frac{AB}{\operatorname{gcd}\left( {\left| A\right| , \left| B\right|}\right)}}&{{\rm{otherwise}}}!!\end{array}} \right.\] {{   int X, Y, T, P;!!   X = A < 0 ? -A : A;!!   Y = B < 0 ? -B : B;!!   P = X*Y;!!   while( Y != 0 ) {!!      T = Y;!!      Y = X % Y;!!      X := T;!!   }!!   return P/X;}} 35. A*B/(A + B) [Harmonic Mean of A and B] (harm) \[R = \left\{ {\begin{array}{*{20}{l}}!!{\rm{anything}}&{{\rm{if\ }}A + B = 0} \\!!{\left\lfloor\frac{AB}{A + B}\right\rfloor _0}&{{\rm{otherwise}}}!!\end{array}} \right.\] {{return A*B/(A + B);}} 36. max(-|B|,min(|B|,A)) [Value of A Clipped to +/-|B|] (clip) \[R = \max\left( -\left| B\right| , \min\left( \left| B\right| , A\right)\right)\] {{   int X;!!   X = B < 0 ? -B : B;!!   return A < -B ? -B : (A > B : B : A);}} 37. A|B| - B|A| [Commutator Bracket of A and B] (comm) \[R = A\left| B\right| - B\left| A\right|\] {{return A*B < 0 ? (2*A*B*((B > 0) - (B < 0))) : 0;}} 38. |A| mod 10 = |B| mod 10 [A and B Have Same Last Decimal Digit] (sameldd) \[R = \left\{ {\begin{array}{*{20}{l}}!!{1}&{{\rm{if\ }}\left| A\right| = \left| B\right|\;\;\left(\operatorname{mod} 10\right)} \\!!{0}&{{\rm{otherwise}}}!!\end{array}} \right.\] {{   int X, Y;!!   X = A < 0 ? -A : A;!!   Y = B < 0 ? -B : B;!!   return X % 10 == Y % 10;}} 39. (A<sup>B</sup> - 1)/(A - 1) [Sum of First B Terms in Power Series 1 + A + A<sup>2</sup> + ...] (pwrsrs) \[R = \left\{ {\begin{array}{*{20}{l}}!!{\rm{anything}}&{{\rm{if\ }}B < 0} \\!!{\rm{anything}}&{{\rm{if\ }}A \leq 1} \\!!{\frac{A^B - 1}{A - 1}}&{{\rm{otherwise}}}!!\end{array}} \right.\] {{return (int)(pow( A, B ) - 1)/(A - 1);}} 40. B<sup>2</sup>/(A<sup>2</sup> + 1) [Squared Distance of the Line Ax + B to the Origin] (sqdist2orgn) \[R = \frac{B^2}{A^2 + 1}\] {{return B*B/(A*A + 1);}}</div><script type="text/javascript">$('#main').html( '<table>' + $('#main').html().replace( /([^\[]+) \[(.+?)\] \((.+?)\) \\\[(.+?)\\\] \{\{(.+?)\}\}/g, '<tr><td>$1</td></tr><tr><td>$2 (<span>$3</span>)</td></tr><tr><td>\\[$4\\]</td></tr><tr><td>$5</td></tr>' ).replace( /!!/g, "\n" ) + '</table>' );</script><script type="text/x-mathjax-config;executed=true">MathJax.Hub.Config( { "HTML-CSS": { preferredFont: "TeX", availableFonts: ["STIX","TeX"], linebreaks: { automatic: true }, EqnChunk: (MathJax.Hub.Browser.isMobile ? 10 : 50) }, tex2jax: { inlineMath: [ ["$", "$"], ["\\\\(","\\\\)"] ], displayMath: [ ["$$","$$"],["\\[", "\\]"] ], processEscapes: true, ignoreClass: "tex2jax_ignore|dno" }, TeX: { noUndefined: { attributes: { mathcolor: "red", mathbackground: "#FFEEEE", mathsize: "90%" }}, Macros: { href: "{}" } }, messageStyle: "none" } );</script><script src="//cdn.mathjax.org/mathjax/latest/MathJax.js?config=TeX-AMS_HTML-full"></script>

The Nature of f

The properties of f are summarized as follows:

• The operations in f are purchased with operation points (OP) and branching points (BP). f is implemented using no more than 120 OP and no more than 20 BP.

  OP and BP purchases costs apply once per code element purchased. For example, the code

  while( A > 0 )
     A = A - B;
  

  incurs the costs of one while loop, one condition, one assignment, and one binary operation, even if the condition, assignment, and binary operation may be evaluated more than once.

• No unary operations are permitted.

• Constant conditions (e.g. true, false, or equivalent) are permitted. All non-constant conditions must be explicit (e.g. no if( A )).

• Only the binary operations and conditions listed under "Binary Operations and Conditions" are permitted.

• The ternary operation <condition> ? <iftrue> : <iffalse> is permitted at the cost of 1 BP plus any cost(s) associated with the operands. Languages that don't explicitly support this ternary operation may implement it as a function.

• f must return a result in worst case O(log max(|A|,|B|)) time or better.

• f may recursively invoke itself at a cost of either 1 BP or 2 OP, but only to a worst case stack depth of O(log max(|A|,|B|)) or better.

• The following control structures are permitted in f:

  • if blocks cost 1 BP each plus the cost of the branch condition
  • if else blocks cost 2 BP each plus the cost of the branch condition
  • if elseif blocks cost 1 BP per if, elseif, or else, plus the cost(s) of any branch conditions
  • while loops and for loops cost 2 BP each plus the cost(s) of any initialization, loop condition, and loop update statements
  • do while loops cost 1 BP each plus the cost of the loop condition
  • goto, break, named break, continue, and named continue statements cost 1 BP each
  • return statements cost 1 BP each, with the exception of the last top-level return that appears in f, which costs nothing

  Programming languages that do not support the above structures may implement them as separate functions/methods/closures or as semantically equivalent code. For example, the code

   while( 1 ) {
      <statement>
      ...
      if( A == B )
         break;
   }
  

  is semantically equivalent to the code

   do {
      <statement>
      ...
   } while( A != B )
  

  and hence the former may be used at the cost of 1 BP (the cost of a do while loop).

Variables and Data Types

Variables and data types in f are summarized as follows:

• No variables may be defined or used by f except for the parameters A, B, L, x, y, z, which may be both read and assigned. Variable assignments may not be chained or nested in expressions (e.g. A = B = 0, w = y == 1 || (z = 10) are not permitted). If a programming language does not support assignment to parameters, parameters may alternatively be copied into proxy local variables at the start of the function. Once this is done, the original parameters may not be referenced.

• Variable assignment incurs no OP or BP costs.

• Assignment to x, y, and z must respect the strict bounds on these variables. For example, if A is not guaranteed to be bounded by [-2³¹  2³¹), the assignment x = A is an error and illegal, even if a programming language would ordinarily allow it. The assignment x = A % 2 (with the semantics of the % operator defined below) is legal since all values of A are guaranteed to yield a legal value of x.

  Note that these same restrictions apply when passing arguments to recursive invocations of f.

• It is recommended that A, B, L, x, y, z all be represented using the same type, but this is not a requirement. Implicit casts, explicit casts, method calls, and/or explicit function calls for converting between data types are allowed in all contexts, provided that both:

  • no clipping, truncation, or wraparound occurs as a result of the conversion
  • all operations on all data types are homomorphic to operations on the integers (notwithstanding the limited range of x, y, and z)

• Constants may be defined at no cost, but may only have values in the range [-2³¹  2³¹). Constants with values outside this range can be realized via binary operations (e.g. 123456789*987654321) but these operations incur costs as normal.

  A constant may be defined using any data type and converted (implicitly or explicitly) to any data type so long as the conversion respects the rules listed above.

• A, B, L are ideally represented by a "big integer" type while x, y, z are best represented as big integers or signed 32-bit ints, but these are not requirements. In particular, an implementation of f may choose to represent all variables using bounded data types, which is allowable subject to two restrictions:

  • under no circumstances may non-ideal effects such as clipping, truncation, floating point precision errors, etc. be used or exploited in the implementation of f
  • any implementation of f relying on bounded data types that has these types replaced with unbounded counterparts must function properly over all inputs in this expanded domain

Binary Operations and Conditions

Only the following set of binary operations and conditions may be used in the implementation of f. Each operation/condition has a cost of 1 OP. Operations/conditions may be implemented in any way (e.g. via infix operators, function calls, method calls, etc.) provided they are stateless and they conform exactly to the given definitions.

<style>tr:first-child { font: bold 18px Times New Roman,Times,serif; }</style><style>td { text-align:center; }</style><style>tr:nth-child(2n) { background-color:#eee; }</style><style>tr:not(:first-child) td:nth-child(3) { font-family: Courier New,monospace; white-space: pre; }</style><script type="text/javascript" src="http://code.jquery.com/jquery-1.10.1.min.js"></script><div id="main">addition \[x + y\] {{x + y}} subtraction \[x - y\] {{x - y}} multiplication \[xy\] {{x*y}} integer division with truncation towards zero* \[\left\lfloor\frac{x}{y}\right\rfloor _0\] {{x/y}} remainder of integer division* \[x - y\left\lfloor\frac{x}{y}\right\rfloor _0\] {{x % y}} modulo** \[x \operatorname{mod} \left| y\right|\] {{int k, q;!!k = y < 0 ? -y : y;!!q = x % k;!!return q < 0 ? q + k : q;}} binary left shift \[{\begin{array}{*{20}{l}}!!{2^y x}&{{\rm{if\ }}y \geq 0} \\!!{\left\lfloor\frac{x}{2^{-y}} \right\rfloor _0}&{{\rm{otherwise}}}!!\end{array}}\] {{y >= 0 ? x*(1 << y) :!!   x/(1 << -y)}} binary right shift \[{\begin{array}{*{20}{l}}!!{\left\lfloor\frac{x}{2^y} \right\rfloor _0}&{{\rm{if\ }}B \geq 0} \\!!{2^{-y} x}&{{\rm{otherwise}}}!!\end{array}}\] {{y >= 0 ? x/(1 << y) :!!   x*(1 << -y)}} logical AND \[{\begin{array}{*{20}{l}}!!{1}&{{\rm{if\ }}\left( x \neq 0\right) \wedge \left( y \neq 0\right)} \\!!{0}&{{\rm{otherwise}}}\end{array}}\] {{x && y}} logical OR \[{\begin{array}{*{20}{l}}!!{1}&{{\rm{if\ }}\left( x \neq 0\right) \vee \left( y \neq 0\right)} \\!!{0}&{{\rm{otherwise}}}\end{array}}\] {{x || y}} equality (Dirac delta) \[{\begin{array}{*{20}{l}}!!{1}&{{\rm{if\ }}x = y} \\!!{0}&{{\rm{otherwise}}}\end{array}}\] {{x == y}} inequality \[{\begin{array}{*{20}{l}}!!{1}&{{\rm{if\ }}x \neq y} \\!!{0}&{{\rm{otherwise}}}\end{array}}\] {{x != y}} less than \[{\begin{array}{*{20}{l}}!!{1}&{{\rm{if\ }}x < y} \\!!{0}&{{\rm{otherwise}}}\end{array}}\] {{r < y}} greater than \[{\begin{array}{*{20}{l}}!!{1}&{{\rm{if\ }}x > y} \\!!{0}&{{\rm{otherwise}}}\end{array}}\] {{x > y}} less than or equal to \[{\begin{array}{*{20}{l}}!!{1}&{{\rm{if\ }}x \leq y} \\!!{0}&{{\rm{otherwise}}}\end{array}}\] {{x <= y}} greater than or equal to \[{\begin{array}{*{20}{l}}!!{1}&{{\rm{if\ }}x \geq y} \\!!{0}&{{\rm{otherwise}}}\end{array}}\] {{x >= y}} bitwise AND of absolutes \[\begin{array}{*{20}{l}}!!{\sum\limits_k {{x_k}{y_k}{2^k}} {\rm{\ given}}} \\!!{\,\,\,\,\,\,\,\left| x \right| = \sum\limits_k {{x_k}{2^k}} } \\!!{\,\,\,\,\,\,\,\left| y \right| = \sum\limits_k {{y_k}{2^k}} } \\!!{\,\,\,\,\,\,\,{x_k},{y_k} \in \left\{ {0,1} \right\}\,\,\forall \,k}!!\end{array}\] {{(x < 0 ? -x : x) &   !!(y < 0 ? -y : y)}}</div><hr><div>*division by zero is a fatal error<br>**modulo zero is a fatal error</div><script type="text/javascript">$('#main').html( '<table cellspacing="0"><tr><td>Operation</td><td>Definition</td><td>C Code (gcc)</td></tr>' + $('#main').html().replace( /([^\[]+) \\\[(.+?)\\\] \{\{(.+?)\}\}/g, '<tr><td>$1</td><td>\\[$2\\]</td><td>$3</td></tr>' ).replace( /!!/g, "\n" ) + '</table>' );</script><script type="text/x-mathjax-config;executed=true">MathJax.Hub.Config( { "HTML-CSS": { preferredFont: "TeX", availableFonts: ["STIX","TeX"], linebreaks: { automatic: true }, EqnChunk: (MathJax.Hub.Browser.isMobile ? 10 : 50) }, tex2jax: { inlineMath: [ ["$", "$"], ["\\\\(","\\\\)"] ], displayMath: [ ["$$","$$"],["\\[", "\\]"] ], processEscapes: true, ignoreClass: "tex2jax_ignore|dno" }, TeX: { noUndefined: { attributes: { mathcolor: "red", mathbackground: "#FFEEEE", mathsize: "90%" }}, Macros: { href: "{}" } }, messageStyle: "none" } );</script><script src="//cdn.mathjax.org/mathjax/latest/MathJax.js?config=TeX-AMS_HTML-full"></script>

Objective

Your objective is to write a function or a program containing a function that implements as many of the 40 operations of f as possible. When invoked at the top level, the arguments of f are assigned as follows:

• A and B specify the two general operands for the operation being selected. For any of the 40 listed operations where the result is not symmetric in A and B, you may return a result for swapped A and B if desired. For example, the function A + sgn(B - A) may alternatively return the value of B + sgn(A - B). Operations with swapped operands should be documented in your submission.

• L must always be zero when passed to the top level invocation of f. Recursive invocations of f may pass any legal value to L.

• x, y and z collectively specify the operation to be performed. This datum can be encoded any way you desire (respecting the limited range of these parameters). Your submission should include a list of at least one (x,y,z) tuple per implemented operation that causes f to compute the result for that operation. You may assume that only these tuples will be passed to a top level invocation of f, hence f may exhibit arbitrary behaviour (including errors and/or illegal operations) if undocumented tuples are passed to top level invocations.

  As with L, recursive invocations of f may pass any legal values to x, y, and z. The results of any such intermediary operations need not be documented.

Scoring

Scoring rules are as follows:

• If f does not implement all 40 operations, score 10 points per implemented operation plus 1 point per unused BP plus 1 point per unused OP.
• If f does implement all 40 operations, score 400 points plus 50 points per unused BP plus 25 points unused OP.

The highest scoring submission is the winner.

Answer 26

Origami Code Golf

I like origami (especially unit origami), but lack the patience to actually complete a project.

Sounds like a wonderful job for a computer!

Objective

Make a program or function that accepts a series of numbers (see next part) and outputs a folded version of a 1 x 1 square.

Input

You will receive a list of numbers {a,b,c,d,e,f},{g,h,i,j,k,l}... (curly braces only added for clarity) Each set of numbers corresponds to 3 coordinates (a,b), (c,d) and (e,f). (a,b) and (c,d) each lie on the unit square (which also means that it is in the first quadrant). (e,f) lies within the unit square, but on a portion of the paper that is not on the line formed by (a,b) and (c,d).

(a,b) and (c,d) determine the line over which to fold the paper.

The portion of the paper that (e,f) lies in determines which side of the paper remains stationary during the fold. You may assume that this value will always lie on a portion of the square (e.g. not on a part of the square that is not there because of a fold).

For example, the input 0.5, 0, 0.5, 1, 0.25, 0.5 means that one should fold the paper in half over the vertical line at 0.5, with the left side remaining stationary.

Each fold (set of input numbers) is sequential, so one fold is made after another.

For example, if the previous example was followed by the input 0, 0.5, 1, 0.5, 0.75, 0.75, the paper should be folded over the horizontal line at 0.5, with the top part remaining stationary.

Output

Your program or function must only output (graphically) the resulting shape and rotation of the folding. It is not required to output the correct location or size.

Test Cases

input 0, 0.5, 1, 0.5, 0.5, 0.75 -

input 0, 0, 1, 1, 0.25, 0.5 -

input - 0.5, 1, 1, 0, 0.25, 0.5, 0, 0.25, 1, 0.25, 0.25, 0.75 -

input - 0.5, 0, 1, 0.5, 0.5, 0.5, 1, 0.5, 0.5, 1, 0.5, 0.5, 0.5, 1, 0, 0.5, 0.5, 0.5, 0, 0.5, 0.5, 0, 0.5, 0.5, 0, 0.25, 1, 0.25, 0.5, 0.5

This is code-golf, so shortest code (in bytes) wins.

Answer 27

Phoneword generator

This is code-golf

Goal

The goal is to write the shortest phoneword generator.

Input

As input you get for just a sequence of numbers (0-9). Given via stdin.

Output

You should write the first 15 possible results to stdout bonus points if the output only contains real words. The words need to have the exact same length like the input string.

What if there are less than 15 options?

Then you can just make up words.

Phoneword

A phoneword, is a sequence of characters, that is typed with letters in your phone which map to the numbers they display.

How to treat 0 and 1

If the input contains a 0 or a 1, you should treat them as 0 and 1. To make a word with them anyway, you can use leetspeak.

Mapping

For the mapping check this picture:

Taken from wikipedia

As example I use codegolf itself: 26334653 translates to CODEGOLF it also gives many more words, here is a list.

Bonus

You can divide the amount of characters by 2, if your code gives only words which are in listed in the Oxford dictionary. For that you are allowed to use a web api to check them.

Answer 28

Generate a Random Boolean Expression

code-golf random generation

In this challenge, you generate a random Boolean expression -- and then evaluate it.

Input

Nothing, or a random seed if your program requires one.

Output

A random Boolean expression and its value, formatted as a string

<expr> = <value>

The expression should be generated according to the following BNF grammar:

<expr> ::= "0" | "1"
         | "(" <expr> "^" <expr> ")"
         | "(" <expr> "v" <expr> ")"
         | "(" <expr> ">" <expr> ")"
         | "~" <expr>

Here, ^ stands for binary AND, v for binary OR, > for implication, and ~ for NOT. Whitespace is not significant. The correct value for the expression should be self-explanatory. Some correct outputs include

0 = 0
~ (~1 ^ 1) = 1
((1v1) ^ ~(0 >(1 ^ ~~~0))) = 0

Detailed Rules

Assuming a perfect random number generator, your program must be able to generate any valid Boolean expression with nonzero probability (discounting whitespace). You must use you language's standard RNG, or one of higher quality.

You can write either a function or a full program, and a function can either return its result or print it to STDOUT. The fewest bytes wins, and standard loopholes are disallowed.

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I'd like some input on whether this challenge is essentially similar to either this or this.

Answer 29

Operator, i can't remember my phone number... code-challenge quine

"Hello? Operator? How do i get my phone to tell me its own number?"

The challenge is to write a quine -- from your cellphone. Not a smartphone with a virtual keyboard, mind you. One of the old phones, where to get a 'c' you have to press 2 three times.

Because programmers are lazy, you want to do it in the least amount of keypresses.

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A previous challenge (Calculate cell-phone keypresses) was to calculate the amount of keypresses it takes to produce a set of characters on a cellphone keyboard.

The challenge there wrote out all the keymappings well, so i'll just quote it here.

The keymaps are:

1:1
2:abcABC2
3:defDEF3
4:ghiGHI4
5:jklJKL5
6:mnoMNO6
7:pqrsPQRS7
8:tuvTUV8
9:wxyzWXYZ9
0:<space><newline>0

To type exaMPle TExt 01 , you would press 33 99 2 6666 77777 555 33 0 8888 33333 99 8 0 <a 1-sec pause here in real life but we'll ignore it>000 1 for a total of 37 keypresses.

The * key brings up a map of special characters:

.,'?!
"-()@
/:_;+
&%*=<
>£€$¥
¤[]{}
\~^¡¿
§#|`

with the first one (.) highlighted. You can move to highlight the required character using rectangular navigation keys and it takes another keypress to select.

So to insert $, you would press *↓↓↓↓→→→<select> i.e. a total of 9 key-presses.

This means, that if you use a = 3 in your code, that is a (1), space (1), = (8), space (1), 3 (7), for a total of 18, even though it's only 5 bytes.

So as not to rule out languages/entries that use characters outside of this range, you can reach it with #, insert, special, select, {type the Unicode number of the character}, select for a total of 5 + Unicode #. I suppose you could use this trick to reduce the number of keypresses via *.

Scoring

Your score is the number of keypresses used to type out the code. There is a Stack Snippet that you can use to calculate. It automatically picks the lower number if you could use either * or #.

The entry with the lowest score after 2 weeks wins!

Answer 30

Find longest alphabet path (code-golf)

You are given a 2d array of size nxn that is filled with lowercasel letters a-z. Your goal is to find the longest continous path by only moving up/down/left/right. A path is a sequence of cells of the 2d grid, where the successor of the current cell must be a neighbour that is above, below, left or right. Also, each cell of the array can only be visited once per sequence. The value (the lowercase letter) of the successor must right before or after the one in the current cell (if the current cell has the value c, the successor must have value b or d).

Output

You have to solve two tasks:

• The challenge stated above
• The challenge stated above plus another restriction: successors can only have the next letter in the alphabet, but not the previosu (if the current cell has the value c the successor must have the value d)

The output must consist of two n x n grids the same size as the input, each for one of the two tasks. The grids have to be the identical again, but all the unused cells that are not part of the longest sequence have to be set to a whitespace. If there are two or more longest sequences, only one arbitrary one of them has to be in the output.

Testcases (more to be added)

Input:  Out1:  Out2:     
ababa   ababa  ab         
babab   babab        
ababa   ababa        
babab   babab        
ababa   ababa

Input:  Out:  Out:
aba     aba   ab
aba
aba

abcd  abcd  abcd
hgfe  hgfe  hgfe
gfeb  gfeb  
babc  babc