This should fail, it will incorrectly judge the string "abbb"

Your list comprehension can be replaced by replicateM 4 perms

Works, thanks!

This line:

[ '(1|((1&(0^1))&(0&0)))' ]

is in your list 3 times, there are probably more duplicates.

In C++, the random test cases include tests with empty words (length 0). This is not expected, given the description, and worse, the answer is expected to be false, while the straightforward implementation will answer true.

It took me a while to figure out why my perfect solution was being rejected.

I also own a 4x4x4 snake cube, and also couldn't solve it. A few years back i wrote a Haskell program to solve it, i could reuse my code today. :) Thanks for making this.

Needs better test cases, at first i didn't read the assignment well, and i made a solution that only checks for occurance of 'n' and 'B', but does not check for the same index. It was accepted anyway.

An O(n) solution is still feasable, the Haskell version even tests this way.

To counter this, why not set the upper limit to 10^9 instead of 10^6?

Or even 10^10000, it still will be really fast with the right code.

Agree that == True should be left of, but i like the style otherwise

The random test cases need slightly more precision, or higher accepted error. I got this failure on my first try:

Expected actual value 1.8743956307381016e-3 to approximately equal expected value 1.8743983442063511e-3 (accepted relative error: 1.0e-6) (after 64 tests): -6.279467554143704 30

I tried the same code a second time, then it worked.

head . sort... now that you mention it, i feel bad :)

on the other hand, sort is a lazy merge sort, so it's still linear time, if a bit convoluted...

I deleted a line and it will works :)

I feel this Kata is too similar to Almost Even

In stead of implementing safeHead yourself, you can use listToMaybe from Data.Maybe.

I like your name better though.

Confirmed, thanks!