ACM ICPC World Finals 2015
Shortest judge solution: 332 bytes. Shortest team solution (during contest): 343 bytes.
This was the easiest problem in the set, and every team solved it in 47 minutes.. Simply go through the points in increasing order, keeping track of the maximum seen so far. When processing a new value, compare its difference to the maximum seen so far and save this difference if it is the largest seen so far.