thanks for the help. I restricted the number of loops, output everything to console and spotted mmy mistake. Took a while to work around it and it's probably ugly AF but it works. Pleased.

only got one loop which holds true while the program counter (pc) -pretentious I know - is less than the length of the program which means it carries out the final command on length -1, incements and then stops. I put several console outputs in the program and spotted a nested if that wasn't properly nested but even after fixing that it still times out. I trace tabled it and it's fine but with out knowing what the failing test is I have no chance of guessing where my error is. Logically it seems to work but clearly doesn't. I don't seem to be able to hit the buffer limit so can't get an ut put from the final tests. Frustrating

A monster, but, hey...it works. Celebrate your monster and ignore the doubters

Mine is defo O to n. One loop, one pass per value. Still times out. I can't see a more simple solution without using some esoteric C# weirdness.

finally someone else who coded it as complicated as I did...LOL