// Description
Given an array of n integers, find the contiguous subarray (containing at least one number) with the largest sum and output that sum.
// Input
The first line contains an integer n (1 <= n <= 10^5). The second line contains n integers a_i (-10^4 <= a_i <= 10^4).
// Output
A single integer: the maximum subarray sum.
// Hint
Kadanes algorithm runs in O(n).