I found one interesting solution in Java 8. I think it's the top rated solution.
I am very puzzle by ONE piece:
[no code spoiler please]
As I understand it, 'b' is the next item to be added, and everything after -> determines HOW it will be sorted. The first condition is that the two items are not equal (in absolute value).
Assuming that's true, the the absValue of that item is subtracted from the item it's tested against ?¿?¿?¿
I hope my question is clear. If not I can try again.