Given an array of numbers, find the maximum sum of any contiguous subarray of the array. For example, given the array [34, -50, 42, 14, -5, 86], the maximum sum would be 137, since we would take elements 42, 14, -5, and 86. Given the array [-5, -1, -8, -9], the maximum sum would be 0, since we would not take any elements. Do this in O(N) time.
Examples:
>>> coding_problem_49([34, -50, 42, 14, -5, 86])
137
>>> coding_problem_49([-5, -1, -8, -9])
0