LeetCode 53. 最大子序和

方法一：贪心

思路：只要sum＞0，则下轮sum可能＞ans

class Solution {
public:
    int maxSubArray(vector<int>& nums) {
        int len = nums.size(), ans = INT_MIN, sum = 0;
        for (int i = 0; i < len; ++i) {
            sum += nums[i];
            ans = max(ans, sum);
            if (sum < 0) sum = 0;//只要sum＞0，则下轮sum可能＞ans
        }
        return ans;
    }
};