No information is given about the order of checking the pixels. Each person can assume a completely different search order and arrive and completely different answers because of this line: "summing the differences between... the pixel that was matched last with the new candidate pixel."

The order matters.

Laziness

I know very little C++, lol.

test5() in Java sample tests has a problem as it doesn't call the TripleDouble() method through the Kata class. It generates a compile-time error.

I get that array1 and array2 must have the same length, but must each element in array1 be the "same" as only one other in array2?

I had the same problem when I was using my iPad yesterday. My connection wasn't slow so I'm thinking it's a devicee thing.