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.

Sandbox FAQ

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Discussion

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• Parts of the challenge you found unclear
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Answer 1

Making a programable computing chip

Make a programable chip with 8000 commands ROM and 48 16-bit unsigned words RAM initalized with zero.

---

These commands should be supported:

a = b + c  # mod 65536
a = b - c
a = b * c
a = b / c  # undefined behavior if c==0
a = b % c
a = b > c  # return 0 or 1
a = b >= c
a = b == c
a = b != c
if a goto b 
if !a goto b
call a, b  # store ip of next command to b and goto a, then can return
input a
output a
a = [b] # You can decide constant k and l, such that [kn+l] is rn. 
[a] = b # Using undefined [n] is UB

where a, b, c can be r0-r47 or a constant of a 16-bit integer or the ip of a command. Writing to a constant is a nop, so input 42 discards an input. Mixing ip and integer, running out of commands are undefined behavior.

For example,

L1: input r1
    r0 = r0 + r1
    output r0
    if !0 goto L1
    r2 = r1 + L1

takes input, and output sum of all inputs modulo 65536. r2 = r1 + L1 is undefined behavior, but since it's never executed it's not a problem.

---

The circuit consists of controlled gates (x,y,c,t), meaning that wire x and wire y are connected if wire c was active(t=1) or inactive(t=0), and programable wire (x,y,0,0), meaning that wire x and wire y can be programmed to be connected.

At the beginning, none of the wires, except IO wires(discuss later), is active. In each step, any wire connected to wire 0, whether directly or indirectly, is active.

IO is used to connect multiple such component. It contains 18 wires, where 16 of them store an integer to be passed, and two A and B meaning if there's data on the wire. When sender send, sender negate A; when reciever recieve, B negated. Therefore, there's data on the wire iff A!=B.

We write A on input, B on input, A on output, and B on output of the chip, as 4, 8, 5, 9, respectively, and the 16-bit input on 16-31, output on 32-47. You can active wires where you are expected to read from, but your chip should handle with another such chip (so if you write to input, you should handle cases when output is inputted).

For example, {(0,5,4,1),(0,8,9,1)} output zero whenever recieving an input.

---

You should submit a circuit (a set of 4-elem tuples) and a compiler. Smallest circuit win.

Answer 2

Ariadne's String code-challengegeometry

Given a \$ 20 \times 20 \$ grid, start at any arbitrary point. Then starting from this point, draw a sequence of straight lines each attached to two points on the grid. In addition, the lines must be in strictly increasing length, and such that no two intersect or touch each other. Call the number of lines drawn \$ n \$. The diagram below shows an example of a smaller \$ 5 \times 5 \$ grid, where \$ n = 5 \$. However, the maximum length for a \$ 5 \times 5 \$ grid is actually \$ n = 9 \$ (Try to find it yourself!).

This is code-challenge, meaning the answer with the largest \$ n \$ wins!

Checker program coming soon

Sandbox

• Anything unclear?
• How to position image on the right and text on the left (it looks better)

Answer 3

Fixed Point of cos(x)

Fixed points are any such values where, given a function f, x = f(x) = f(f(x)) = . . .

There exists a "fixed point" for the cosine function, where x = cos(x) = cos(cos(x))= . . . (you may have unknowingly come across this by repeatedly pressing "cos" on a scientific calculator).

Using the knowledge that x = f(x), one can think of a fixed point as the intersection of the graphs of y = x and y = f(x). If we let f(x)=cos(x), the graph looks like this:

Your task is to calculate the x-value of the fixed point of cos(x) 0.73908513 . . . to at least 3 digits' precision (i.e. at least as far as 0.739).

Rules

• No input is to be taken for the program

• This is code-golf so the shortest answer (in bytes) wins

---

Questions for Sandbox:

• Is the question clear enough as it is written?

• I have searched, but I am still paranoid: is this a duplicate?

• Are the tags code-golf and math suitable? Or should I also include number?

• Should I allow input? It seems unnecessary for solving the problem to me

• How far should the precision be extended?

Answer 4

Boolean Variable Satisfiability code-golf

You are given a logical expression containing 'true', 'false', 'variable' and some common boolean operators. Assuming that all variables are independent and can be freely set to either true or false, is it possible assign values to the variables such that the expression evaluates to true?

For example, the expression true and variable and not variable can indeed evaluate to true (if the first variable is true and the second is false). However, the expression false and variable cannot ever evaluate to true, regardless of what values you set the variable to.

Note that you are not required to construct a solution; you only need to determine whether or not it exists.

Input

You are given an expression in Reverse Polish notation, using the following symbols:

• T - True
• F - False
• V - Variable
• & - Logical AND
• | - Logical OR
• ^ - Logical XOR
• ! - Logical NOT

As an example, TFV!T^|& represents the expression true and (false or (not variable xor true)).

Output

The program should output a truthy value iff the expression can be evaluated to true for some set of variable assignments. Otherwise, a falsy value should be outputted.

Examples

Here are a few example expressions and their expected outputs:

TF&
False

FV|V&
True

VV!&
True

VV^!
True

VV&F|VVT|!&V!&&
False

VV&F|VVT|!&V!^&
True

TFV!T^|&
True

VT|!V&F|VF&!T^^
False

Scoring

This is code-golf, so the shortest answer wins.

Sandbox Comments

I've written this as if I would post it right away. However, seeing as this is the first challenge I've written for this site, any and all input is welcome so as to make sure it's of an acceptable standard.

Answer 5

Constellation Enumeration in Game of Life

Yet another trivial Conway's Game of Life challenge.

A stable constellation is a still life that is composed of two or more non-interacting objects.

You task is to take the valid object list, and output a list of all possible constellations. The objects cannot be rotated or reflected. All of the objects are still lives themselves.

A sample implementation is here.

Sandbox

• Any advices on the input and output format? Plain text, RLE, or every Golly-accepable form?
• Any test cases?
• Other recommendations.

Answer 6

Convert NFA to DFA as quickly as possible.

Input

Your input will be an NFA. In order to be able to test your code, it needs to be able to handle an NFA in the following format. This is taken directly from GAP (and slightly simplified).

Automaton( Type, Size, Alphabet, TransitionTable, Initial, Accepting )

For the input, Type will always be "nondet". Size is a positive integer representing the number of states of the automaton. Alphabet is the number of letters of the alphabet. TransitionTable is the transition matrix. The entries are lists of non-negative integers not greater than the size of the automaton are also allowed. Initial and Accepting are, respectively, the lists of initial and accepting states.

Example input:

Automaton("nondet", 4, 2, [[[], [2], [3], [1, 2, 3, 4], [2, 4]],
                                [[], [1, 3, 4], [1], [2, 4]]], [1], [2, 3])

This is slightly easier to read as a transition table.

   |  1    2             3                4
--------------------------------------------------
 a |      [ 2 ]         [ 1, 2, 3, 4 ]   [ 2, 4 ]   
 b |      [ 1, 3, 4 ]   [ 1 ]            [ 2, 4 ]   
Initial state:    [ 1 ]
Accepting states: [ 2, 3 ]

Output

Your output must be a DFA that is equivalent to the input NFA. There is no need for your DFA to be minimal. For the output, Type will always be "det". Size is a positive integer representing the number of states of the automaton. Alphabet is the number of letters of the alphabet. TransitionTable is the transition matrix. The entries are non-negative integers not greater than the size of the automaton. The states should be labelled by consecutive integers. Initial and Accepting are, respectively, the lists of initial and accepting states. In the case of the example above, this would be:

Automaton("det", 2, 2, [[2, 2], [2, 2]], [1], [])

As a transition table this is:

   |  1  2  
-----------
 a |  2  2  
 b |  2  2  
Initial state:   [ 1 ]
Accepting state: [  ]

(It is now clear this is a DFA that will not accept any input strings.)

Test cases:

1. Input:

Automaton("nondet",2,4,[[[1], [2]], [[2], []], [[2], []] , [[1], [2]]],[1],[1, 2]))

As a transition matrix:

   |  1       2
-------------------
 a | [ 1 ]   [ 2 ]   
 b | [ 2 ]           
 c | [ 2 ]           
 d | [ 1 ]   [ 2 ]   
Initial state:    [ 1 ]
Accepting states: [ 1, 2 ]

Here is the diagram of the NFA.

Output:

Automaton("det",3, 4,[[1, 2, 3], [2, 3, 3], [2, 3, 3], [1, 2, 3]], [1],[1, 2])

As a transition matrix:

   |  1  2  3  
--------------
 a |  1  2  3  
 b |  2  3  3  
 c |  2  3  3  
 d |  1  2  3  
Initial state:    [ 1 ]
Accepting states: [ 1, 2 ]

Here is the diagram of the DFA.

2. Input:

Automaton("nondet",7,4,[[[1, 3, 4, 5], [2], [3], [3, 4], [3, 5], [], []], [[2, 3, 4, 7], [3], [], [], [3, 7], [3, 4], []], [[2, 3, 5, 6], [3], [], [3, 6], [], [], [3, 5]], [[1, 3, 6, 7], [2], [3], [], [], [3, 6], [3, 7]]],[1],[1, 2, 3, 4, 5, 6, 7])

Output:

3. Input:

Automaton("nondet",12, 4,[[[1, 3, 5, 6], [2, 4, 7, 8], [3], [6], [3, 5], [3, 6], [4, 7], [4, 8], [4, 7], [4, 8], [], []], [[2, 3, 5, 10], [3, 4, 7, 12], [6], [], [4, 7], [3, 10], [], [4, 12], [3, 5], [4, 12], [4, 7], []], [[2, 3, 6, 9], [3, 4, 8, 11], [6], [], [3, 9], [4, 8], [4, 11], [], [4, 11], [3, 6], [], [4, 8 ]], [[1, 3, 9, 10], [2, 4, 11, 12], [3], [6], [4, 11], [4, 12], [], [], [3, 9], [3, 10], [4, 11], [4, 12]]],[1],[1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12])

Output:

Automaton("det",39, 4,[[1, 2, 3, 3, 5, 24, 7, 8, 22, 20, 8, 32, 18, 18, 3, 19, 25, 18, 19, 20, 25, 22, 23, 24, 25, 25, 24, 23, 5, 2, 35, 32, 19, 19, 35, 36, 36, 36, 36], [1, 38, 1, 23, 15, 9, 11, 26, 23, 28, 26, 10, 9, 26, 1, 3, 22, 26, 3, 28, 22, 23, 1, 15, 3, 3, 15, 1, 28, 27, 10, 27, 23, 23, 38, 15, 28, 15, 28], [1, 5, 1, 1, 1, 4, 12, 6, 6, 31, 31, 37, 37, 30, 5, 5, 29, 37, 3, 21, 4, 21, 4, 4, 4, 29, 30, 29, 1, 5, 29, 37, 5, 3, 29, 3, 3, 2, 2], [1, 16, 3, 4, 3, 21, 7, 18, 33, 39, 14, 13, 13, 14, 15, 16, 17, 18, 19, 34, 21, 34, 3, 19, 19, 16, 38, 15, 4, 33, 17, 18, 33, 34, 16, 19, 34, 38, 39]],[7],[ 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39])

4. Input:

Automaton("nondet",25,4,[[[1, 3, 6, 7], [2, 4, 8, 9], [3, 5, 10, 11], [6], [7], [3, 5, 6, 10, 18], [3, 5, 7, 11, 19], [4, 8], [4, 9 ], [5, 10], [5, 11], [4, 5, 8, 10, 22], [4, 5, 9, 11, 23], [5, 10], [5, 11], [], [], [5, 10, 18], [5, 11, 19], [5, 10, 22], [5, 11, 23 ], [], [], [], []], [[2, 3, 6, 13], [3, 4, 8, 15], [4, 5, 10, 17], [7], [], [4, 5, 8, 10, 18], [3, 5, 13, 17, 21], [5, 10], [4, 15], [], [5, 17], [3, 5, 6, 10, 22], [4, 5, 15, 17, 25], [4, 8], [5, 17], [5, 10], [], [], [5, 17, 21], [], [5, 17, 25], [5, 10, 18], [], [5, 10, 22], []], [[2, 3, 7, 12], [3, 4, 9, 14], [4, 5, 11, 16], [7], [], [3, 5, 12, 16, 20], [4, 5, 9, 11, 19], [4, 14], [5, 11], [5, 16], [], [4, 5, 14, 16, 24], [3, 5, 7, 11, 23], [5, 16], [4, 9], [], [5, 11], [5, 16, 20], [], [5, 16, 24], [], [], [5, 11, 19], [], [5, 11, 23]], [[1, 3, 12, 13], [2, 4, 14, 15], [3, 5, 16, 17], [6], [7], [4, 5, 14, 16, 20], [4, 5, 15, 17, 21], [5, 16], [5, 17], [], [], [3, 5, 12, 16, 24], [3, 5, 13, 17, 25], [4, 14], [4, 15], [5, 16], [5, 17], [], [], [], [], [5, 16, 20], [5, 17, 21], [5, 16, 24], [5, 17, 25]]],[1],[1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25])

Output:

Automaton("det",266,4,[[1, 127, 50, 50, 115, 249, 50, 8, 257, 10, 151, 12, 13, 14, 81, 78, 34, 106, 137, 107, 21, 22, 82, 89, 71, 43, 43, 62, 63, 63, 44, 10, 179, 171, 214, 265, 206, 38, 137, 152, 21, 151, 71, 22, 41, 41, 47, 13, 49, 50, 50, 210, 50, 210, 116, 90, 64, 49, 207, 207, 207, 62, 232, 64, 64, 89, 151, 236, 236, 70, 71, 236, 116, 260, 128, 75, 13, 38, 77, 133, 14, 82, 13, 13, 77, 235, 64, 64, 231, 206, 138, 91, 91, 206, 90, 264, 137, 169, 10, 10, 41, 71, 232, 228, 232, 21, 21, 107, 106, 110, 111, 266, 256, 114, 114, 116, 251, 251, 116, 114, 114, 111, 266, 260, 122, 182, 127, 128, 129, 213, 132, 132, 129, 49, 49, 138, 138, 138, 249, 71, 43, 43, 210, 235, 183, 214, 132, 265, 206, 138, 232, 64, 64, 153, 153, 64, 152, 152, 82, 236, 236, 82, 116, 116, 64, 207, 266, 64, 231, 169, 171, 250, 227, 70, 175, 175, 176, 10, 47, 178, 178, 110, 111, 266, 260, 122, 266, 127, 213, 49, 49, 152, 257, 153, 257, 90, 90, 183, 250, 264, 62, 228, 229, 82, 82, 206, 64, 266, 249, 249, 249, 242, 213, 214, 64, 116, 114, 114, 50, 50, 236, 236, 261, 115, 152, 251, 8, 228, 229, 229, 231, 232, 237, 235, 235, 236, 237, 235, 235, 235, 235, 235, 235, 242, 242, 242, 115, 251, 249, 250, 116, 116, 116, 207, 64, 265, 266, 257, 256, 266, 264, 261, 260, 264, 265, 266], [1, 125, 1, 114, 114, 121, 115, 3, 23, 19, 13, 15, 230, 28, 201, 202, 16, 84, 123, 103, 105, 208, 114, 84, 172, 199, 199, 119, 83, 83, 123, 170, 16, 31, 27, 26, 25, 104, 102, 23, 28, 13, 120, 208, 48, 103, 19, 230, 239, 1, 114, 218, 115, 219, 82, 140, 23, 208, 204, 216, 216, 119, 174, 119, 119, 84, 13, 115, 115, 50, 120, 50, 82, 204, 262, 79, 230, 104, 203, 85, 28, 114, 230, 230, 203, 3, 23, 119, 96, 96, 96, 123, 102, 140, 208, 3, 200, 200, 98, 97, 103, 120, 119, 120, 119, 28, 105, 103, 105, 54, 3, 23, 141, 1, 250, 50, 82, 114, 50, 1, 250, 3, 3, 219, 219, 125, 54, 263, 124, 124, 27, 124, 223, 208, 239, 25, 208, 208, 120, 120, 217, 217, 217, 120, 120, 142, 142, 141, 140, 140, 174, 174, 174, 204, 216, 23, 119, 23, 250, 114, 114, 250, 162, 162, 159, 205, 159, 159, 208, 123, 170, 1, 219, 50, 208, 208, 123, 177, 177, 19, 170, 173, 172, 172, 199, 199, 23, 186, 185, 184, 184, 23, 120, 216, 23, 140, 208, 120, 1, 3, 119, 120, 114, 114, 250, 239, 119, 3, 121, 3, 120, 219, 212, 212, 23, 50, 1, 250, 1, 114, 50, 114, 219, 114, 23, 114, 3, 120, 114, 114, 208, 119, 125, 121, 3, 50, 54, 120, 3, 120, 121, 3, 120, 218, 219, 217, 114, 114, 3, 1, 250, 250, 250, 253, 252, 173, 172, 120, 125, 3, 3, 219, 219, 3, 54, 3], [1, 1, 249, 249, 6, 1, 1, 247, 7, 130, 167, 17, 11, 66, 33, 33, 131, 136, 10, 32, 150, 9, 112, 36, 149, 112, 149, 56, 167, 37, 181, 130, 35, 147, 139, 51, 139, 11, 10, 234, 147, 37, 148, 113, 136, 136, 146, 24, 249, 1, 1, 249, 249, 249, 139, 6, 238, 127, 134, 238, 134, 9, 148, 238, 134, 167, 36, 50, 249, 247, 73, 249, 51, 139, 112, 167, 76, 76, 11, 167, 80, 73, 67, 66, 66, 135, 58, 58, 112, 139, 233, 100, 100, 2, 6, 95, 10, 32, 130, 130, 99, 94, 94, 56, 149, 150, 147, 150, 136, 51, 51, 51, 7, 51, 51, 51, 7, 6, 139, 139, 139, 2, 58, 134, 139, 7, 1, 112, 112, 249, 238, 238, 112, 249, 127, 238, 233, 238, 1, 149, 112, 149, 249, 135, 7, 139, 238, 51, 139, 238, 112, 238, 233, 234, 234, 134, 234, 190, 112, 50, 249, 73, 139, 51, 238, 134, 51, 134, 148, 32, 147, 145, 145, 145, 258, 259, 180, 130, 146, 189, 189, 51, 51, 134, 134, 139, 2, 1, 249, 127, 249, 191, 191, 191, 188, 188, 188, 188, 198, 197, 196, 196, 195, 187, 187, 139, 233, 134, 127, 127, 127, 49, 249, 139, 243, 211, 211, 211, 210, 210, 210, 210, 95, 209, 241, 209, 126, 117, 117, 9, 112, 112, 50, 50, 50, 50, 50, 50, 49, 49, 127, 127, 127, 249, 249, 249, 7, 7, 1, 247, 51, 139, 211, 134, 134, 51, 51, 7, 7, 2, 126, 145, 139, 247, 51, 51], [1, 51, 3, 4, 4, 7, 7, 50, 73, 61, 11, 12, 40, 109, 101, 93, 45, 18, 19, 20, 21, 64, 161, 29, 193, 118, 193, 65, 11, 42, 19, 59, 30, 46, 163, 164, 163, 40, 39, 57, 46, 42, 246, 60, 18, 21, 61, 158, 72, 50, 51, 53, 53, 3, 55, 55, 57, 246, 156, 64, 65, 64, 155, 64, 65, 11, 29, 68, 69, 236, 160, 72, 73, 55, 157, 11, 154, 154, 40, 11, 46, 160, 225, 192, 192, 86, 87, 88, 157, 118, 155, 19, 39, 74, 161, 239, 92, 92, 166, 254, 20, 144, 88, 240, 65, 109, 108, 21, 21, 50, 50, 73, 73, 50, 247, 236, 73, 161, 72, 3, 5, 54, 86, 239, 3, 51, 50, 64, 64, 161, 165, 64, 157, 161, 245, 165, 60, 64, 51, 240, 161, 240, 4, 144, 51, 55, 57, 73, 55, 57, 157, 157, 155, 57, 64, 156, 64, 87, 118, 160, 161, 248, 163, 164, 165, 168, 164, 168, 60, 19, 108, 3, 3, 72, 64, 60, 19, 194, 194, 61, 59, 247, 247, 193, 193, 5, 74, 7, 69, 244, 69, 156, 240, 65, 74, 74, 246, 143, 219, 86, 88, 144, 222, 222, 226, 72, 60, 239, 52, 54, 143, 239, 72, 72, 215, 221, 219, 224, 219, 220, 221, 222, 239, 220, 215, 222, 54, 160, 160, 161, 64, 64, 160, 68, 236, 236, 236, 160, 239, 240, 244, 245, 246, 69, 72, 161, 51, 160, 50, 50, 248, 118, 226, 255, 255, 248, 248, 160, 160, 245, 245, 72, 72, 236, 236, 236]],[12],[2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100, 101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 111, 112, 113, 114, 115, 116, 117, 118, 119, 120, 121, 122, 123, 124, 125, 126, 127, 128, 129, 130, 131, 132, 133, 134, 135, 136, 137, 138, 139, 140, 141, 142, 143, 144, 145, 146, 147, 148, 149, 150, 151, 152, 153, 154, 155, 156, 157, 158, 159, 160, 161, 162, 163, 164, 165, 166, 167, 168, 169, 170, 171, 172, 173, 174, 175, 176, 177, 178, 179, 180, 181, 182, 183, 184, 185, 186, 187, 188, 189, 190, 191, 192, 193, 194, 195, 196, 197, 198, 199, 200, 201, 202, 203, 204, 205, 206, 207, 208, 209, 210, 211, 212, 213, 214, 215, 216, 217, 218, 219, 220, 221, 222, 223, 224, 225, 226, 227, 228, 229, 230, 231, 232, 233, 234, 235, 236, 237, 238, 239, 240, 241, 242, 243, 244, 245, 246, 247, 248, 249, 250, 251, 252, 253, 254, 255, 256, 257, 258, 259, 260, 261, 262, 263, 264, 265, 266])

5. Input:

Automaton("nondet",38,4,[[[1, 3, 7, 8], [2, 4, 9, 10], [3, 5, 11, 12], [4, 6, 13, 14], [7], [8], [3, 5, 7, 11, 23], [3, 5, 8, 12, 24], [4, 6, 9, 13, 25], [4, 6, 10, 14, 26], [5, 11], [5, 12], [6, 13], [6, 14], [4, 5, 9, 11, 31], [4, 5, 10, 12, 32], [5, 6, 11, 13, 33], [5, 6, 12, 14, 34], [6, 13], [6, 14], [], [], [5, 11, 23], [5, 12, 24], [6, 13, 25], [6, 14, 26], [5, 11, 31], [5, 12, 32], [6, 13, 33], [6, 14, 34], [6, 13, 25], [6, 14, 26], [], [], [6, 13, 33], [6, 14, 34], [], []], [[2, 3, 7, 16], [3, 4, 9, 18], [4, 5, 11, 20], [5, 6, 13, 22], [8], [], [4, 5, 9, 11, 23], [3, 5, 16, 20, 28], [5, 6, 11, 13, 25], [4, 6, 18, 22, 30], [6, 13], [5, 20], [], [6, 22], [3, 5, 7, 11, 31], [4, 5, 18, 20, 36], [4, 6, 9, 13, 33], [5, 6, 20, 22, 38], [5, 11], [6, 22], [6, 13], [], [6, 13, 25], [5, 20, 28], [], [6, 22, 30], [6, 13, 33], [5, 20, 36], [], [6, 22, 38], [5, 11, 23], [6, 22, 30], [6, 13, 25], [], [5, 11, 31], [6, 22, 38], [6, 13, 33], []], [[2, 3, 8, 15], [3, 4, 10, 17], [4, 5, 12, 19], [5, 6, 14, 21], [8], [], [3, 5, 15, 19, 27], [4, 5, 10, 12, 24], [4, 6, 17, 21, 29], [5, 6, 12, 14, 26], [5, 19], [6, 14], [6, 21], [], [4, 5, 17, 19, 35], [3, 5, 8, 12, 32], [5, 6, 19, 21, 37], [4, 6, 10, 14, 34], [6, 21], [5, 12], [], [6, 14], [5, 19, 27], [6, 14, 26], [6, 21, 29], [], [5, 19, 35], [6, 14, 34], [6, 21, 37], [], [6, 21, 29], [5, 12, 24], [], [6, 14, 26 ], [6, 21, 37], [5, 12, 32], [], [6, 14, 34]], [[1, 3, 15, 16], [2, 4, 17, 18], [3, 5, 19, 20], [4, 6, 21, 22], [7], [8], [ 4, 5, 17, 19, 27], [4, 5, 18, 20, 28], [5, 6, 19, 21, 29], [5, 6, 20, 22, 30], [6, 21], [6, 22], [], [], [3, 5, 15, 19, 35], [3, 5, 16, 20, 36], [4, 6, 17, 21, 37], [4, 6, 18, 22, 38], [5, 19], [5, 20], [6, 21], [6, 22], [6, 21, 29], [6, 22, 30], [], [], [6, 21, 37], [6, 22, 38], [], [], [5, 19, 27], [5, 20, 28], [6, 21, 29], [6, 22, 30], [5, 19, 35], [5, 20, 36], [6, 21, 37], [6, 22, 38]]],[1],[1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38])

Output

6. Input:

Automaton("nondet",67,4,[[[1, 3, 8, 9], [2, 4, 10, 11], [3, 5, 12, 13], [4, 6, 14, 15], [5, 7, 16, 17], [8], [8], [3, 5, 8, 12, 28], [3, 5, 9, 13, 29], [4, 6, 10, 14, 30], [4, 6, 11, 15, 31], [5, 7, 12, 16, 32], [5, 7, 13, 17, 33], [6, 14], [6, 15], [ 7, 16], [7, 17], [4, 5, 10, 12, 40], [4, 5, 11, 13, 41], [5, 6, 12, 14, 42], [5, 6, 13, 15, 43], [6, 7, 14, 16, 44], [6, 7, 15, 17, 45], [7, 16], [7, 17], [], [], [5, 7, 12, 16, 28, 32, 52], [5, 7, 13, 17, 29, 33, 53], [6, 14, 30], [6, 15, 31], [7, 16, 32], [7, 17, 33], [5, 7, 12, 16, 40, 44, 56], [5, 7, 13, 17, 41, 45, 57], [6, 14, 42], [6, 15, 43], [7, 16, 44], [7, 17, 45], [6, 7, 14, 16, 30, 32, 60], [6, 7, 15, 17, 31, 33, 61], [7, 16, 32], [7, 17, 33], [], [], [6, 7, 14, 16, 42, 44, 64], [6, 7, 15, 17, 43, 45, 65], [7, 16, 44], [7, 17, 45], [], [], [7, 16, 32, 52], [7, 17, 33, 53], [7, 16, 44, 56], [7, 17, 45, 57], [7, 16, 32, 60], [7, 17, 33, 61], [7, 16, 44, 64], [7, 17, 45, 65], [], [], [], [], [], [], [], []], [[2, 3, 8, 19], [3, 4, 10, 21], [4, 5, 12, 23], [5, 6, 14, 25], [6, 7, 16, 27], [8], [], [4, 5, 10, 12, 28], [3, 5, 19, 23, 35], [5, 6, 12, 14, 30], [4, 6, 21, 25, 37], [6, 7, 14, 16, 32], [5, 7, 23, 27, 39], [7, 16], [6, 25], [], [7, 27], [3, 5, 8, 12, 40], [4, 5, 21, 23, 47], [4, 6, 10, 14, 42], [5, 6, 23, 25, 49], [5, 7, 12, 16, 44], [6, 7, 25, 27, 51], [6, 14], [7, 27], [7, 16], [], [6, 7, 14, 16, 30, 32, 52], [5, 7, 23, 27, 35, 39, 55], [7, 16, 32], [6, 25, 37], [], [7, 27, 39], [6, 7, 14, 16, 42, 44, 56], [5, 7, 23, 27, 47, 51, 59], [7, 16, 44], [6, 25, 49], [], [7, 27, 51], [5, 7, 12, 16, 28, 32, 60], [6, 7, 25, 27, 37, 39, 63], [6, 14, 30], [7, 27, 39], [7, 16, 32], [], [5, 7, 12, 16, 40, 44, 64], [6, 7, 25, 27, 49, 51, 67], [6, 14, 42], [7, 27, 51], [7, 16, 44], [], [], [7, 27, 39, 55], [], [7, 27, 51, 59], [], [7, 27, 39, 63], [], [7, 27, 51, 67], [7, 16, 32, 52], [], [7, 16, 44, 56], [], [7, 16, 32, 60], [], [7, 16, 44, 64], []], [[2, 3, 9, 18], [3, 4, 11, 20], [4, 5, 13, 22], [5, 6, 15, 24], [6, 7, 17, 26], [8], [], [3, 5, 18, 22, 34], [4, 5, 11, 13, 29], [4, 6, 20, 24, 36], [5, 6, 13, 15, 31], [5, 7, 22, 26, 38], [6, 7, 15, 17, 33], [6, 24], [7, 17], [7, 26 ], [], [4, 5, 20, 22, 46], [3, 5, 9, 13, 41], [5, 6, 22, 24, 48], [4, 6, 11, 15, 43], [6, 7, 24, 26, 50], [5, 7, 13, 17, 45], [7, 26], [6, 15], [], [7, 17], [5, 7, 22, 26, 34, 38, 54], [6, 7, 15, 17, 31, 33, 53], [6, 24, 36], [7, 17, 33], [7, 26, 38], [], [ 5, 7, 22, 26, 46, 50, 58], [6, 7, 15, 17, 43, 45, 57], [6, 24, 48], [7, 17, 45], [7, 26, 50], [], [6, 7, 24, 26, 36, 38, 62], [5, 7, 13, 17, 29, 33, 61], [7, 26, 38], [6, 15, 31], [], [7, 17, 33], [6, 7, 24, 26, 48, 50, 66], [5, 7, 13, 17, 41, 45, 65], [7, 26, 50], [6, 15, 43], [], [7, 17, 45], [7, 26, 38, 54], [], [7, 26, 50, 58], [], [7, 26, 38, 62], [], [7, 26, 50, 66], [], [], [7, 17, 33, 53], [], [7, 17, 45, 57], [], [7, 17, 33, 61], [], [7, 17, 45, 65]], [[1, 3, 18, 19], [2, 4, 20, 21], [3, 5, 22, 23 ], [4, 6, 24, 25], [5, 7, 26, 27], [8], [8], [4, 5, 20, 22, 34], [4, 5, 21, 23, 35], [5, 6, 22, 24, 36], [5, 6, 23, 25, 37], [6, 7, 24, 26, 38], [6, 7, 25, 27, 39], [7, 26], [7, 27], [], [], [3, 5, 18, 22, 46], [3, 5, 19, 23, 47], [4, 6, 20, 24, 48], [4, 6, 21, 25, 49], [5, 7, 22, 26, 50], [5, 7, 23, 27, 51], [6, 24], [6, 25], [7, 26], [7, 27], [6, 7, 24, 26, 36, 38, 54], [6, 7, 25, 27, 37, 39, 55], [7, 26, 38], [7, 27, 39], [], [], [6, 7, 24, 26, 48, 50, 58], [6, 7, 25, 27, 49, 51, 59], [7, 26, 50], [7, 27, 51], [], [], [5, 7, 22, 26, 34, 38, 62], [5, 7, 23, 27, 35, 39, 63], [6, 24, 36], [6, 25, 37], [7, 26, 38], [7, 27, 39], [5, 7, 22, 26, 46, 50, 66], [5, 7, 23, 27, 47, 51, 67], [6, 24, 48], [6, 25, 49], [7, 26, 50], [7, 27, 51], [], [], [], [], [], [], [], [], [7, 26, 38, 54], [7, 27, 39, 55], [7, 26, 50, 58], [7, 27, 51, 59], [7, 26, 38, 62], [7, 27, 39, 63], [7, 26, 50, 66], [7, 27, 51, 67]]],[1],[1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67])

Output

7. Input:

Automaton("nondet",96,4,[[[1, 3, 9, 10], [2, 4, 11, 12], [3, 5, 13, 14], [4, 6, 15, 16], [5, 7, 17, 18], [6, 8, 19, 20], [7 ], [8], [3, 5, 9, 13, 33], [3, 5, 10, 14, 34], [4, 6, 11, 15, 35], [4, 6, 12, 16, 36], [5, 7, 13, 17, 37], [5, 7, 14, 18, 38], [6, 8, 15, 19, 39], [6, 8, 16, 20, 40], [7, 17], [7, 18], [8, 19], [8, 20], [4, 5, 11, 13, 49], [4, 5, 12, 14, 50], [5, 6, 13, 15, 51], [5, 6, 14, 16, 52], [6, 7, 15, 17, 53], [6, 7, 16, 18, 54], [7, 8, 17, 19, 55], [7, 8, 18, 20, 56], [8, 19], [8, 20], [], [], [5, 7, 13, 17, 33, 37, 65], [5, 7, 14, 18, 34, 38, 66], [6, 8, 15, 19, 35, 39, 67], [6, 8, 16, 20, 36, 40, 68], [7, 17, 37], [7, 18, 38], [8, 19, 39], [8, 20, 40], [5, 7, 13, 17, 49, 53, 73], [5, 7, 14, 18, 50, 54, 74], [6, 8, 15, 19, 51, 55, 75], [6, 8, 16, 20, 52, 56, 76], [7, 17, 53], [7, 18, 54], [8, 19, 55], [8, 20, 56], [6, 7, 15, 17, 35, 37, 81], [6, 7, 16, 18, 36, 38, 82], [7, 8, 17, 19, 37, 39, 83], [7, 8, 18, 20, 38, 40, 84], [8, 19, 39], [8, 20, 40], [], [], [6, 7, 15, 17, 51, 53, 89], [6, 7, 16, 18, 52, 54, 90], [7, 8, 17, 19, 53, 55, 91], [7, 8, 18, 20, 54, 56, 92], [8, 19, 55], [8, 20, 56], [], [], [7, 17, 37, 65], [7, 18, 38, 66 ], [8, 19, 39, 67], [8, 20, 40, 68], [7, 17, 53, 73], [7, 18, 54, 74], [8, 19, 55, 75], [8, 20, 56, 76], [7, 17, 37, 81], [7, 18, 38, 82], [8, 19, 39, 83], [8, 20, 40, 84], [7, 17, 53, 89], [7, 18, 54, 90], [8, 19, 55, 91], [8, 20, 56, 92], [8, 19, 39, 67], [8, 20, 40, 68], [], [], [8, 19, 55, 75], [8, 20, 56, 76], [], [], [8, 19, 39, 83], [8, 20, 40, 84], [], [], [8, 19, 55, 91], [8, 20, 56, 92], [], []], [[2, 3, 9, 22], [3, 4, 11, 24], [4, 5, 13, 26], [5, 6, 15, 28], [6, 7, 17, 30], [7, 8, 19, 32], [8 ], [], [4, 5, 11, 13, 33], [3, 5, 22, 26, 42], [5, 6, 13, 15, 35], [4, 6, 24, 28, 44], [6, 7, 15, 17, 37], [5, 7, 26, 30, 46], [7, 8, 17, 19, 39], [6, 8, 28, 32, 48], [8, 19], [7, 30], [], [8, 32], [3, 5, 9, 13, 49], [4, 5, 24, 26, 58], [4, 6, 11, 15, 51], [ 5, 6, 26, 28, 60], [5, 7, 13, 17, 53], [6, 7, 28, 30, 62], [6, 8, 15, 19, 55], [7, 8, 30, 32, 64], [7, 17], [8, 32], [8, 19], [], [6, 7, 15, 17, 35, 37, 65], [5, 7, 26, 30, 42, 46, 70], [7, 8, 17, 19, 37, 39, 67], [6, 8, 28, 32, 44, 48, 72], [8, 19, 39], [7, 30, 46], [], [8, 32, 48], [6, 7, 15, 17, 51, 53, 73], [5, 7, 26, 30, 58, 62, 78], [7, 8, 17, 19, 53, 55, 75], [6, 8, 28, 32, 60, 64, 80], [8, 19, 55], [7, 30, 62], [], [8, 32, 64], [5, 7, 13, 17, 33, 37, 81], [6, 7, 28, 30, 44, 46, 86], [6, 8, 15, 19, 35, 39, 83], [7, 8, 30, 32, 46, 48, 88], [7, 17, 37], [8, 32, 48], [8, 19, 39], [], [5, 7, 13, 17, 49, 53, 89], [6, 7, 28, 30, 60, 62, 94], [6, 8, 15, 19, 51, 55, 91], [7, 8, 30, 32, 62, 64, 96], [7, 17, 53], [8, 32, 64], [8, 19, 55], [], [8, 19, 39, 67], [7, 30, 46, 70], [], [8, 32, 48, 72], [8, 19, 55, 75], [7, 30, 62, 78], [], [8, 32, 64, 80], [8, 19, 39, 83], [7, 30, 46, 86], [], [8, 32, 48, 88], [8, 19, 55, 91], [7, 30, 62, 94], [], [8, 32, 64, 96], [7, 17, 37, 65], [8, 32, 48, 72], [8, 19, 39, 67], [], [7, 17, 53, 73], [8, 32, 64, 80], [8, 19, 55, 75], [], [7, 17, 37, 81], [8, 32, 48, 88], [8, 19, 39, 83], [], [7, 17, 53, 89], [8, 32, 64, 96 ], [8, 19, 55, 91], []], [[2, 3, 10, 21], [3, 4, 12, 23], [4, 5, 14, 25], [5, 6, 16, 27], [6, 7, 18, 29], [7, 8, 20, 31], [8], [], [3, 5, 21, 25, 41], [4, 5, 12, 14, 34], [4, 6, 23, 27, 43], [5, 6, 14, 16, 36], [5, 7, 25, 29, 45], [6, 7, 16, 18, 38], [6, 8, 27, 31, 47], [7, 8, 18, 20, 40], [7, 29], [8, 20], [8, 31], [], [4, 5, 23, 25, 57], [3, 5, 10, 14, 50], [5, 6, 25, 27, 59], [ 4, 6, 12, 16, 52], [6, 7, 27, 29, 61], [5, 7, 14, 18, 54], [7, 8, 29, 31, 63], [6, 8, 16, 20, 56], [8, 31], [7, 18], [], [8, 20 ], [5, 7, 25, 29, 41, 45, 69], [6, 7, 16, 18, 36, 38, 66], [6, 8, 27, 31, 43, 47, 71], [7, 8, 18, 20, 38, 40, 68], [7, 29, 45], [8, 20, 40], [8, 31, 47], [], [5, 7, 25, 29, 57, 61, 77], [6, 7, 16, 18, 52, 54, 74], [6, 8, 27, 31, 59, 63, 79], [7, 8, 18, 20, 54, 56, 76], [7, 29, 61], [8, 20, 56], [8, 31, 63], [], [6, 7, 27, 29, 43, 45, 85], [5, 7, 14, 18, 34, 38, 82], [7, 8, 29, 31, 45, 47, 87], [6, 8, 16, 20, 36, 40, 84], [8, 31, 47], [7, 18, 38], [], [8, 20, 40], [6, 7, 27, 29, 59, 61, 93], [5, 7, 14, 18, 50, 54, 90], [7, 8, 29, 31, 61, 63, 95], [6, 8, 16, 20, 52, 56, 92], [8, 31, 63], [7, 18, 54], [], [8, 20, 56], [7, 29, 45, 69], [8, 20, 40, 68], [8, 31, 47, 71], [], [7, 29, 61, 77], [8, 20, 56, 76], [8, 31, 63, 79], [], [7, 29, 45, 85], [8, 20, 40, 84], [8, 31, 47, 87], [], [7, 29, 61, 93], [8, 20, 56, 92], [8, 31, 63, 95], [], [8, 31, 47, 71], [7, 18, 38, 66], [], [8, 20, 40, 68], [8, 31, 63, 79], [7, 18, 54, 74], [], [8, 20, 56, 76], [8, 31, 47, 87], [7, 18, 38, 82], [], [8, 20, 40, 84], [8, 31, 63, 95], [7, 18, 54, 90 ], [], [8, 20, 56, 92]], [[1, 3, 21, 22], [2, 4, 23, 24], [3, 5, 25, 26], [4, 6, 27, 28], [5, 7, 29, 30], [6, 8, 31, 32], [8], [8], [4, 5, 23, 25, 41], [4, 5, 24, 26, 42], [5, 6, 25, 27, 43], [5, 6, 26, 28, 44], [6, 7, 27, 29, 45], [6, 7, 28, 30, 46], [7, 8, 29, 31, 47], [7, 8, 30, 32, 48], [8, 31], [8, 32], [], [], [3, 5, 21, 25, 57], [3, 5, 22, 26, 58], [4, 6, 23, 27, 59], [4, 6, 24, 28, 60], [5, 7, 25, 29, 61], [5, 7, 26, 30, 62], [6, 8, 27, 31, 63], [6, 8, 28, 32, 64], [7, 29], [7, 30], [8, 31], [8, 32], [6, 7, 27, 29, 43, 45, 69], [6, 7, 28, 30, 44, 46, 70], [7, 8, 29, 31, 45, 47, 71], [7, 8, 30, 32, 46, 48, 72], [8, 31, 47], [8, 32, 48], [], [], [6, 7, 27, 29, 59, 61, 77], [6, 7, 28, 30, 60, 62, 78], [7, 8, 29, 31, 61, 63, 79], [7, 8, 30, 32, 62, 64, 80], [8, 31, 63], [8, 32, 64], [], [], [5, 7, 25, 29, 41, 45, 85], [5, 7, 26, 30, 42, 46, 86], [6, 8, 27, 31, 43, 47, 87], [6, 8, 28, 32, 44, 48, 88], [7, 29, 45], [7, 30, 46], [8, 31, 47], [8, 32, 48], [5, 7, 25, 29, 57, 61, 93], [5, 7, 26, 30, 58, 62, 94], [6, 8, 27, 31, 59, 63, 95], [6, 8, 28, 32, 60, 64, 96], [7, 29, 61], [7, 30, 62], [8, 31, 63], [8, 32, 64], [8, 31, 47, 71], [8, 32, 48, 72 ], [], [], [8, 31, 63, 79], [8, 32, 64, 80], [], [], [8, 31, 47, 87], [8, 32, 48, 88], [], [], [8, 31, 63, 95], [8, 32, 64, 96 ], [], [], [7, 29, 45, 69], [7, 30, 46, 70], [8, 31, 47, 71], [8, 32, 48, 72], [7, 29, 61, 77], [7, 30, 62, 78], [8, 31, 63, 79], [8, 32, 64, 80], [7, 29, 45, 85], [7, 30, 46, 86], [8, 31, 47, 87], [8, 32, 48, 88], [7, 29, 61, 93], [7, 30, 62, 94], [8, 31, 63, 95], [8, 32, 64, 96]]],[1],[1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96])

8. The DFA for 7 plus the NFAs/DFAS for 8, 9, 10, 11 are here as they are too big to paste. For 12, 13, 14, 15 I have only included the NFAs. The files have names k6dfa, k7nfa, k7dfa etc. As an example, the input for problem 7 is k7nfa and the output is k7dfa. Hopefully the rest of the names are clear. If your code is correct for problems 1-11, I am happy to believe it is correct in general.

Score

I will time your code on test cases 1..15 from above of increasing size. Your score will be the largest test case your code can process in less than 10 minutes. If two answers get to the same size then the one that is fastest on that largest test case wins. The test machine is an Intel(R) Xeon(R) CPU E5-2680 v4 @ 2.40GHz. You can use at most 16 of its cores.

Testing

I will check your answers (for the smaller cases) using AreEquivAut .

[Thank you to Christian Sievers for the example NFAs.]

Answer 7

Improved image sampling popularity-contest graphical-output image-processing

Quoting from the ImageMagick documentation of the very simple -sample resizer, "You can think of the image as being divided into an array of regions, and one pixel from each region is selected for the resulting image". Unfortunately, it uses a bad algorithm for choosing the one pixel: it chooses the middle one.

In this challenge, you have to write a program that takes an image and a positive integer \$N\$ (\$N\$ divides the height and the width) as input and outputs the image downscaled by the factor \$N\$. In the output image, every pixel must be taken from the corresponding \$N\times N\$ square in the original image.

[image gallery and settings used]

This is tagged popularity-contest, so the answer with the most upvotes wins!

Answer 8

Fetch me some data internet code-golf code-challenge

This is the fifth post for the second RGS's Golfing Showdown.

Task

Write some code to fetch the updated total number of confirmed infected cases in a territory. The territory you choose to fetch data for will influence your score, so keep that in mind.

Input

Your code takes no input.

Output

You should output an integer or any other sensible representation of it.

Rules

Fetching the data

The data you fetch must be fetched from a URI that must have been online at least since the 25th of April of 2020. You may fetch the most recent data or the data for a specific date, as long as in that date, your territory has a non-zero number of total confirmed cases.

Scoring and Territory

The territory you fetch data for must be a territory listed in the WHO daily situation reports and the numbers you fetch for a given date must be within 10% of the WHO numbers for the same date.

Your score will be the number of bytes minus the length of the longest common substring between your code and the territory you pick, case insensitive.

E.g. If my program is abcdefghijklmno and my territory is Italy I get to shave 2 bytes of my score because of the common substring il (or al).

Sandbox

Are the rules clear enough and well-specified enough?

Answer 9

Posted

Answer 10

This is my first question, so I don't know what exactly I should ask, but I will try. Please advise.

---

Russian roulette

It's Russian roulette! The rules are simple. Shoot a revolver with n slots for bullets and one round inside at your head and you might not die!

Task:

Make a program that takes integer n (you can assume that 10<=n<=128) as input and outputs nothing.

but how do I tell if I'm dead?

The program generates a random number x in the range 0 - (n) inclusive. If x=n the revolver fires and the program exits with an error (you die). Otherwise the program exits normally.

Standard loopholes forbidden, etc.

random game error-message code-golf

---

Sandbox questions:

• This question is short. What can I explain better or add?
• What are good tags to add?
• Should I make it code-golf or popularity contest? Both?
• Too easy?
• This is a joke, will it be misinterpreted?

Answer 11

Revisit sum

---

Why is this language specific?

As much as much as I like challenges to be language agnostic if this challenge were language agnostic it would most certainly be a duplicate of the add two numbers challenge due to our current duplicate policy. And for most languages adding two numbers and adding several numbers are no different. Revisit is not one of those languages.

---

In Revisit adding two numbers is easy.

+@

does the trick. However in this challenge we are going to ask you to do something much more difficult. Take a an arbitrary number of positive integers as input and output the sum of all them.

Your answer should be functioning revisit as per revisit version 0.1.

This is code-golf so answers are scored in bytes with fewer bytes being better.

Answer 12

Compass and straightedge segment reduction code-golf geometry

You are given two points at distance 1, a compass and a straightedge. The challenge is, given a positive integer \$N\$, to find the shortest segment possible to obtain by drawing no more than \$N\$ lines or circles. A segment is defined as a pair of two points such that there is a line connecting them.

This is tagged code-golf, so the shortest answer wins!

Sandbox stuff

• Certain details of compass-and-straightedge constructions are not specified yet.

• Should I allow assuming normal floating point math to be exact, or to require proper arbitrary precision?

• Is the answer trivial? I know that you can, for example, obtain geometric progressions with factor that seems to be \$\tan(x)\$ (and thus perhaps it's optimal to first bisect an angle for a while, then subtract it from a straight angle, and then do this).

More importantly, is this possible? I assume it is, because it seems possible to calculate everything necessary for the basic constructions:

• It's (easily) possible to compare lines and circles for equality
• It's possible to calculate the parameters of a line passing through 2 points.
• It's possible to calculate the parameters of a circle - that is, find the point and the radius given the point and the radius.
• It's possible to calculate the point of intersection between 2 lines (if it exists).
• It's possible to calculate the points of intersection between a line and a circle.
• It's possible to calculate the points of intersection between 2 circles.

Is that enough for a proof?

Answer 13

Continue an arithmetic-geometric progression code-golf math

^{note: not related to these arithmetic-geometric sequences}
An arithmetic progression has the property that \$a_n = \frac{a_{n-1} + a_{n+1}}2\$ - that is, every term is the arithmetic mean of its neighbours.
A geometric progression has a similar property: \$a_n = \root\of{a_{n-1}\cdot a_{n+1}}\$ - every term is the geometric mean of its neighbours.

There's also the arithmetic-geometric mean \$AGM(x, y)\$! It's defined as follows: define two sequences as \$a_0 = x, g_0 = y, a_{n+1} = \frac{a_n+g_n}2, g_{n+1}=\root\of{a_n g_n}\$. The sequences converge to the same number, the arithmetic-geometric mean of \$x\$ and \$y\$.

Now I can define another progression: an arithmetic-geometric progression has the property that \$a_n = AGM(a_{n-1}, a_{n+1})\$.

As input you are given two real numbers - the first two terms of an arithmetic-geometric progression. The challenge is to find the third one with absolute or relative error not exceeding \$10^{-5}\$ (and output it).

This is tagged code-golf, so the shortest answer wins!

Answer 14

Emulate a Schmitt trigger

Given low and high cutoff points, and a list of input readings, generate a list of output states at those points.

• If an input reading is greater than the high cutoff point then the output is always in the high cutoff state.
• If an input reading is lower than the low cutoff point then the output is always in the low cutoff state.
• At least one of the above comparisons must be a strict inequality. (Please make both comparisons strict unless this would consume additional bytes.)
• If the initial reading is between the two cutoff points the the output must be deterministic (i.e. the same for each run with the same inputs).
• In all other cases the output remains in the same state.
• It is valid for both cutoff points to be the same value.
• The input readings may be taken in any convenient format, but it must be capable of handling at least 94 different values.
• decision-problem The output for each input reading must be one of two distinct values.

This is code-golf, so the shortest program or function that breaks no standard loopholes wins!

Answer 15

Subtract a list code-golf

You are given a list of boolean values as input. You have to find its difference.

The difference of a list of one value is equal to the value itself. The difference of a list with \$N\$ values is defined as $$(\text{the difference of the first }\lfloor\frac{N}2\rfloor\text{ items}) - (\text{the difference of the last }\lceil\frac{N}2\rceil\text{ items})$$

This is tagged code-golf, so the shortest answer wins!

[todo: examples]

Answer 16

Analyze the flow

code-golfgridcounting

Posted

Answer 17

There are \$a\$ honest man(always tell the truth), \$b\$ dishonest man(always tell lie), and \$c\$ random man(tell random Y/N). How many times at least should you ask one of them a yes/no question to guarantee you get knowledge of who they are? You may assume that it's possible.

Test cases:

(a,b,c) -> ans
(1,1,0) -> 1
(1,1,1) -> 3
(0,0,2) -> 0

code-golf

Notes:

• I don't know if there's clever way, but anyway brute-force work
• It's enough if you can only ask an expression about who they are. If you ask them "what will A answer if I ask B" the answer is just "(A is liar) xor B". "Did A tell lie when answering B" is just "(A's answer) xor B". Questions about the current ask or future ask may lead to paradox and are not allowed.
• Actually it's possible to identify them iff there are less than half of random answerer, or an edge case that all are random answerers. Only considering honest and random, if there are more honest than random, ask them same question and do a majority vote gets answer to the question. If there are same honest and random, and random tell as if they are honest and real honest are random, you can't tell the difference.

Answer 18

The game of scrabble is played by placing lettered tiles on a grid to form words. The words being formed must read from left to right, or up to down on the grid. The words must appear in the official Scrabble dictionary, and all letters placed on the grid must be part of a valid word. This challenge will focus on a specific technique for playing a simplified version of Scrabble.

A useful technique when playing Scrabble is to add a single letter to an existing word that is already on the board to form a new word. Write a program or function that, when given a dictionary, finds the longest series of words that can be formed by adding a single letter to another word to form a new word.

Example

You are given the following dictionary:

at
ate
rate
elate
crate
belate
belated

Your submission should output:

['at', 'ate', 'rate', 'crate']

An invalid output would be:

['at', 'ate', 'elate', 'belate', 'belated']

because 'elate' cannot be formed by adding a single letter to 'ate'.

Note that this challenge is not about finding the longest word that can be formed by adding a single letter to another word, but about finding the longest chain of words that can be formed in such a way. Which means that this answer:

['elate', 'belate', 'belated']

is wrong, because it only has three steps, whereas the first example has four.

Winning Criteria

Code-golf, so shortest code wins. I/O is flexible. Standard loopholes apply. Take dictionary as a list, file, delimited string, or whatever you want. Output can be sent to stdout, returned as a single string (with delimiter), or list of strings.

Test Cases

TODO

Answer 19

Uniform necklace sampling code-challenge random

The challenge is, given a number \$N\$, to produce a random binary necklace of length \$N\$. All possible necklaces must have the same probability of being chosen.

[TODO: more about necklaces]

Scoring

Solutions are compared first by asymptotic memory complexity in \$N\$ (lower is better), and, in case of a tie, by size (lower is better).

Sandbox stuff

(I do intend to use code-golf as only a tiebreaker)

• How to tag this question the most correctly?

Answer 20

Posted: SELECT ALL FROM SelectQL WHERE (answer="short" OR NOT length=10000)

Answer 21

Solve some diplomatic issues

You are given a set of moves in a theoretical Diplomacy game. We're not going to handle validation of moves being legal or not, simply attempt to resolve a turn.

Here are the simplified rules to Diplomacy (full rules here):

• There are two types of units: Armies and Fleets. Armies can only move on land, Fleets on land and in the sea. You can safely ignore this, because we're assuming that all of the moves you've been given are at least theoretically valid.
• There are four types of moves: Hold (stay in place), Move, Support (a certain other unit), Convoy.
• When two or more units end up in the same country, whichever unit has the most support stays. Each unit without the most support (or each unit tied for the most) returns to its original country. A unit which is not Moving and which is not tied for the most support is Dislodged.
• A Fleet can Convoy an Army through its space to another space. That convoy is cancelled if the Fleet is Dislodged. Only a Fleet in a sea space can Convoy.
• A unit can support another unit holding or moving into an adjacent country if it can move into that country (Armies can't Support Fleets in the sea).
• A supporting unit which is attacked ceases to support, unless it is supporting an attack on the unit attacking it. If it is dislodged, it ceases to support in any case.
• The Beleaguered Garrison rule: If a unit is attacked by two units with the same amount of support, the attacked unit is not Dislodged, and the attackers return to their original countries.

You will receive a list of moves. Each move will be in the following format:

Power Unit_type Origin_country Move_type Destination_country

There is no Destination_country if a unit holds (or you can insert a placeholder). Destination_country for Support or Convoy is the Origin_country of the unit being Supported or Convoyed. For example, you could get:

E F Eng M Pic
F A Pic H
G A Bel S Eng

This means:

English Fleet in the English Channel Moves to Picardy
French Army in Picardy Holds
German Army in Belgium Supports the Fleet in the English Channel to Move to Picardy

Your output should be the location of each unit after the move. Any Dislodged unit should be marked as such.

Output format:

Power Unit_type Country Dislodged?

For the example given above, the output should be:

E F Pic
F A Pic D
G A Bel

The more difficult part of this is in regards to convoys. A convoy fails if there is no valid path for the army to take. For instance, if we have:

E F Nth C Den
E A Den M Hol
F F Eng M Nth
F F Bel S Eng

The French fleets dislodge the English Fleet in the North Sea, and the convoy does not take place. But if we also had

E F Hel C Den

There would still be a valid path for the English Army and the convoy would succeed.

Paradoxes

Be warned, there are paradoxes in Diplomacy. These are to be treated as undefined behaviour; any output is acceptable where

1. Each unit is listed
2. There is only one non-dislodged unit per country
3. In any country with a dislodged unit there is a non-dislodged unit
4. Each non-moving unit is listed in its origin country
5. Each moving unit is listed either in its origin country or its destination country

Note that, in particular, each unit being in its starting country is a valid output.

Adjacency list

For use with convoys, it's helpful to know which countries are adjacent to which other countries. (Everything is assumed to be valid, but it may not be clear whether a convoy with a single cut link is still possible otherwise).

You may assume that this list is available to you in any format: a function that takes two countries and returns true/false, a variable, a file, etc. In any case, the list itself does not add to your byte count.

[To be added]

Input/Output Formats

You can use any Input/Output formats you choose, as is standard.

Questions for the sandbox

• How much clearer does my description of the rules of Diplomacy need to be?
• Does this sound like an interesting challenge?

code-golfboard-game

Answer 22

Enforce Social Distancing! code-challenge test-battery

Related to Maintain Social Distancing!.

As in that challenge, there is a 2-dimensional array of 1s and 0s representing people. In it, social distancing is maintained if and only if all 1s are at least 6 squares apart, where distance metric used is \$|\Delta x| + |\Delta y|\$ (rectilinear or Manhattan).

The challenge here is to move some people in a given 2D array so that social distancing is maintained. It's guaranteed that it's possible to do so. Your program's score on a given input is the total distance moved by all people.

Your program's running time must not exceed 10 seconds on any of the test cases.

This is tagged test-battery, so there is a large set of inputs your programs will be tested on [TODO: actually create it]. The program with the lowest total score on all of these inputs wins.

Sandbox stuff

• Is this currently a bad idea for the reasons specified by Shaggy in the following comment?

  I am sorry but I have downvoted this for what others may perceive to be a trivial reason: Code Golf is one of the few things I have left where I can escape how fucked my world has become; I absolutely do not want to come here to be reminded that I can't hug my family and friends.

• Is there an optimal algorithm? (I hope not)

Answer 23

Shorten the numbers

These numbers are taking up far too many bytes on my computer. Create a function/program to shorten any number using only Alphanumeric characters as the output.

Scoring

Scoring is based on optimized-output. Shortest number of characters produced for the following randomly generated numbers (plus one special number with repetition) wins. Add the number of output characters output for the 5 test numbers together for total score.

• 94949267912781
• 75477115147709
• 79547324913976
• 12345678998765
• 11111122222222

The score of the non-optimized numbers = 70. (14 * 5)

Sandbox questions

• does scoring make sense?
• should I include a sample script, output, or both?
• should I be more clear the answers should work on any number? (ie. "replacing each test number with one character is disallowed")?

Answer 24

Posted.

Answer 25

Match the entire lyrics of All-Star

The challenge is simple: create a program/function that, when given a string consisting of the entire lyrics to All-Star as they appear in this paste (or not), output whether or not they are, in fact, the entire lyrics. The given string may be off by one of two characters, or something completely different, like Moby Dick (approximately). Output may consist of any of two values that map to true and false. They could be 0 and 1, or t and f, or whatever you like so long as there are two distinct values. You can choose to print the output or return it (if you are a program or a function). This is code-golf, so shortest answer in bytes wins!

Answer 26

Golf me a ^Bookmarklet Quine

Given a javascript program (or any utf-8 text) of arbitrary length, output it in my simplified version of URI form, like a bookmarklet. You can use https://mrcoles.com/bookmarklet/ as reference. Output should be in the form

javascript:[input with percent-encoding for special characters]

Special characters are any character that is not

• Alphabetic (upper or lower)
• a digit
• the characters .,-,_, or ~ (period, hyphen, underscore, tilde)

Your program "should convert all other characters to bytes according to UTF-8, and then percent-encode those values"^w

A percent-encoding mechanism is used to represent a data octet in a component when that octet's corresponding character is outside the allowed set or is being used as a delimiter of, or within, the component. A percent-encoded octet is encoded as a character triplet, consisting of the percent character "%" followed by the two hexadecimal digits representing that octet's numeric value. For example, "%20" is the percent-encoding for the binary octet "00100000" (ABNF: %x20), which in US-ASCII corresponds to the space character (SP). source

Lowercase hex is okay, but uppercase is preferred.

This is code golf, standard loopholes are prohibited, programs should handle input up to 20 lines and output in a single line.

The Twist (so it's not a duplicate)

If run with no input or just a newline (your choice), the program should output itself in the same format as if the program's source was inputted normally.

Examples

In                                              Out

[blank]                                         javascript:[the%20program%27s%20source]
g/re/p                                          javascript:g%2Fre%2Fp
https://www.youtube.com/watch?v=dQw4w9WgXcQ     javascript:https%3A%2F%2Fwww.youtube.com%2Fwatch%3Fv%3DdQw4w9WgXcQ
alert("test!")                                  javascript:%7Balert(%22test!%22)

code-golf quine

---

sandbox questions

• What should I add?
• What tags does this need?
• Are my examples inconsistent?
• What parts of the challenge are redundant?

Answer 27

Comment: might be too similar to previous mutual quine challenge?

Collaboration/quasi-quine challenge

Write a valid submission (A) which prints the code for another competitor's valid submission (B). The languages used in A and B must be different.

Clarifying rules

If B prints the code for a third submission, C, it is not required that A and C be different languages. Similarly, the authors of A and B must be different, but A and C need not be. (More different languages/authors score higher, however.)

The shortest chain is for A to print B and B to print A.

Note that if A prints B, and B prints C, but C is not valid for some reason, then neither A nor B are valid either.

It is acknowledged that the validity of your submission may change over time, due to factors beyond your control. Try not to let this worry you too much. :)

Input

None

Output

Just the code described above. Nothing extraneous.

Scoring

Scoring is (A + L) * 100 + C where:

• A is the number of distinct authors that directly or indirect print your solution. So if you are Q, and Z=>X=>Q=>X, your "A" is 2. (Each submission only has one author, the "answerer".)
• L is the number of distinct languages in your quine circle, along the same lines as for authors. (Each submission only has one language. "Distinct" means really different, not just different versions or implementations of the same languages.)
• C is the length of your solution in bytes.

(So, for a given circle of quines, all the submissions will have similar scores, with the length of the submission as tie-break.)

Standard loopholes are forbidden.

Answer 28

Price this word code-golfnumberstring

So, I'm going shopping in the Word Market™. There are shelves of words which I can buy around me, but I only have one dollar bills and the change machines at the market are broken. To add to the problem, there are words with... non-word characters in them. That's no good, I can't buy those... can you help me figure out which words I can buy and which I can't?

Task

So, I can only buy words that consist of only alphabetical characters and are worth a dollar. To determine a word's value, you have to sum the letters in the word where A = 1¢, B = 2¢... to Z = 26¢. I'm too lazy to look at the output and judge whether it is equal to one dollar (100 cents), so you'll need to return a specific value for words equal to a dollar (...or 100 cents) and a specific value for not equal to a dollar (I'm going to stop including this).

I'll also offer a bonus byte reduction: if your code returns whether the word is less than a dollar, equal to a dollar, greater than a dollar, or invalid (e.g. <, =, >, x), your score will be multiplied by 3/4.

SANDBOX NOTE: Is this a balanced bonus value?

Examples

Word          Non-bonus value     Bonus value

a                  false               <
b                  false               <
printera           false               >
$word              false               x
printer            true                =

And here's a JavaScript snippet you can use if you want to check for non-bonus validity:

(it's also 52 bytes; you can use it by calling f())

f=s=>([...s].map(x=>a+=parseInt(x,36)-9),a==100),a=0

Anyways, standard loopholes apply, shortest answer in bytes wins (but I'll add shortest answers for esoteric and functional languages)... you get the idea.

Answer 29

Magic card trick: Hide information by flipping cards

_{(This is inspired by a series of questions on puzzles.stackexchange.com: 10, 8, 7)}

Fix two integers m and u. Your task is to perform the following magic trick:

• A Magician brings a pack of m distinct cards, and leaves the room.

• In their absence, a volunteer from the audience shuffles the deck and arranges all cards in a line, in any order they want.

• Still in the absence of the magician, their assistant flips u cards. On the table are the n cards, still in the order chosen by the volunteers, but u are face down, leaving only m−u cards face up.

• The magician returns, and from the order of the cards alone, knows each card.

Input:

m - number of cards.

u - number of cards to flip face down.

• You may assume 0 < u < m.

Output, if the trick is possible for m and u:

f - an mapping assigning to each sequence the order the assistant will create by flipping cards.

• If the trick is to work, this mapping must be bijective.
• Use the integers 1...m (or 0...m−1), or single letters as card values.
• Use any meaningful way to express f: a hash maps, a table, a function.
• Use a fixed placeholder for any face-down cards.

Output, if the trick is impossible for given values of m and u

This case should be indicated in a meaningful way.

Example output (m=3, u=1):

Using the digits 0, 1, and 2 as cards, and _ for their flipside:

012 01_
021 0_1
102 _02
120 12_
201 2_1
210 _10

_{(For these values of m and u, this isn't very impressive as a magic trick, of course.)}

Example output (m=4, u=2):

Using 1, 2, 3, and 4 for the cards and 0 for their flipside, and a JSON representation:

{"1234":"0034","1243":"0043","1324":"0024","1342":"0042","1423":"0023","1432":"0032",
"2134":"0104","2143":"0103","2314":"0014","2341":"0041","2413":"0013","2431":"0031",
"3124":"0120","3142":"0102","3214":"0204","3241":"0201","3412":"0012","3421":"0021",
"4123":"4003","4132":"0130","4213":"0203","4231":"0230","4312":"0302","4321":"0301"}

_{This is correct because as required, the keys are all permutations of 1234, each value has two cards face-down and the other cards match the original sequence, and each value appears only once.}

Scoring

This is code-golf. Shortest solution wins.

Answer 30

_