LeetCode53 Maximum Subarray 最大子串和

问题描述：
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: 6

Explanation: [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.
题源：here；完整实现：here
思路：
一个one-pass的方案：从头开始记录输入数组的和maxSum，当maxSum<0时重新记录，并用另一个变量记录maxSum的最大值。代码如下：

class Solution {
public:
    int maxSubArray(vector<int>& nums) {
        int maxSum = INT_MIN, result = INT_MIN;
        for (int i = 0; i < nums.size(); i++){
            if (maxSum < 0) maxSum = nums[i];
            else maxSum += nums[i];
            result = max(result, maxSum);
        }

        return result;
    }
};