原题：https://leetcode.com/problems/maximum-subarray/

Given an integer array `nums`

, find the contiguous subarray (containing at least one number) which has the largest sum and return its sum.

**Example:**

Input:[-2,1,-3,4,-1,2,1,-5,4],Output:6Explanation:[4,-1,2,1] has the largest sum = 6.

**Follow up:**

If you have figured out the O(*n*) solution, try coding another solution using the divide and conquer approach, which is more subtle.