Brainfuck. How check on palindrome?

Question

The problem is to check if sequence is palindrome using Brainfuck.

input is a sequance of numbers

output 0 if it is not palindorme, else 1.

I have one idea: Say, we have sequance 1 2 3 2 1. We can memorise first cell from our array in variable(do this using operation '!'),

then change 1 to 0(do this using operation '0'),array will be 0 2 3 2 1,
then we go to the end of array until we meet 0 (do this using '>[>]'),
then we take number from variable and get sequance 0 2 3 2 1 1.
Next step should be to compare two last numbers, if they are equal continue algo from begining else do something...

I do not know how to implement last step.

where are we on this question ? was my response helpful ? – Uri Goren May 24 '15 at 09:27 — Uri Goren, May 24 '15 at 09:27

score 2 · Answer 1 · edited May 23 '17 at 12:16

2

please excuse me if I won't write the entire program in brainfuck,

This is the main idea:

Read input (pointer should be at last character afterwards)
memorize character
Set value to 0
Go to first [<]
Compare to memorized character (see Brainfuck compare 2 numbers as greater than or less than)
If not equal, print 1
If the next (>) cell array is 0, print 0
Move to pointer to end [>]
Go back to step 2

edited May 23 '17 at 12:16

Community

answered May 16 '15 at 19:56

Uri Goren

`2. memorize character` - how ? – Scony Jun 03 '15 at 11:21
@Scony I think he means read the input and add it to the tape with the `,` command. – ASCIIThenANSI Jun 27 '15 at 02:56

1 Answers1