Maybe it would help if the input strings are included in the random tests reports, rather than only what's expected.

it`s good kata, but I think that a level for this 4-5 kyu maybe?

Too easy for those who know the mathematical property...

Finding a better algorithm that works with the given constraints IS coding, even if you don't like it.

I really like this solution.

Shows me that I included one too many steps, utilising min_element AND distance to retrieve the index of the next smallest element.

how to take 16 lines of code and turn it into 5 ;)
very well done, nice to see how smooth it can be.
also best/fastest solution due to use of min/max ^^

ok given up now. good handful of hours put into it and several days later i must simply accept that i am lacking some knowledge somewhere to complete it.

seems i can get it down to like O(nlogn)'ish, which isn't nearly enough;
so i must be lacking some mathematical background, some systematic knowledge of xor or a completely different approach (or all of the above hehe).

either way i am apparently not on ready for this yet :P
awesome assignment for getting my readup on binary manipulation and masking.

if you got any hints to each theorom i should read up on it would be appriciated (don't like leaving it unsolved :P )

for others with the same issue, it is:
column index ^ row index =time they can give. (in decimal: base 10)

example: row 4 col 7= 4^7=3 as seen.

i am having issues figuring out what dataset you are asking us to use?
after too much time wasted on it i can only assume it is decyphor the array from the example and implement an incremental initiated array in that manner.
if that is so it would have helped a lot on the enjoyment, and frustration, if that was stated in the description as this is where i would look for such info :)