Can the cursor reach the bottom?
A cursor position is valid if either of its two sides touches whitespace (i.e. a space or a newline(CR+LF or LF, depending on your OS)). The input will always consist of valid cursor positions.
This takes one input(a character matrix), and for a cursor on the up right corner of the input, can the cursor reach the bottom of the input?
Example input:
..... Same, delete text like this in order
......
. . . .
. Same to get normal input
...... Same
The cursor can reach the bottom in this case. This process of moving the cursor will work: down, right(touches spaces on the left), down(touches spaces on the right), down, right(touches spaces on both sides) 6 times, and down(touching spaces and a linefeed).
Notably, this will also work:
Code Golf deletes trailing whitespace by default
..
.
trailing
The cursor starts at the up-right corner. After moving right two times, it can move down (due to touching a newline character). Then, it can move down, which touches the bottom of the line.
This example will not work:
...
... Same reason as above
The cursor cannot move down, as there is no sufficient whitespace to be touched.