Problem Statement (story changed so it's easier to understand): The are N problems and M programmers. The ith programmer (1 <= i <= M) can complete the task in ti minutes. Each programmer solves on problem at time. What is the shortest time required for all the programmers to finish all of their tasks?

Example:

Input: N = 5, M = 2, t1 = 7, t2 = 12

Output: 24

Any suggestions? Thanks.