i'm deceased

You should think for yourself, not in my place.

This code doesn't follow typical styling, which would have the line broken into a couple new lines and helps dramatically with readability. I think some believe one-liners look cooler.

How did you solve problem?

Yeah, you're right, this is one of those times when all the tests pass and you forget to refactor.

"redundant", like in posting the same comment twice?

Are you sure that blindly subtracting values from std::vector::end() makes for a safe operation and therefore a valid loop condition?