I can't pass long testing and don't understand logic of this task with negative numbers.

Testing for -85, 1, 29, 51, -19, 37, 2, -20 and 7

Expected: 71
Got: 48

My result number is 48 - it's difference between max(37) and min(-85), with absolute values - 85-37=48. Ok, I'm not right, buy how they got 71?
It's difference between what values?

I'm upset with this kata, because I've a right solution, but it's not efficient enough. It has passed 7 basic tests and first 30 random, but from 31 comes random millions b/w marbles and my simple solution is not enough. I just got Execution Timed Out (12000 ms) =(