LeetCode53：最大子序列和

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

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.

解题思路

动态规划

https://leetcode-cn.com/problems/maximum-subarray/solution/hua-jie-suan-fa-53-zui-da-zi-xu-he-by-guanpengchn/

class Solution {
public:
    int maxSubArray(vector& nums) {
        if(nums.empty())
            return 0;      
        int ans = nums[0];
        int sum = 0;
        for(int i = 0; i < nums.size(); i ++)
        {
            if(sum > 0)
                sum += nums[i];
            else
                sum = nums[i];
            ans = std::max(sum, ans);
        } 
        return ans;
    }
};

进阶：分治法

https://leetcode-cn.com/problems/maximum-subarray/solution/dong-tai-di-gui-fa-he-fen-zhi-jie-jue-by-fu-shi-sa/