leetcode 53. 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: 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.

很经典的题目了，记得初始化为最小值。

本质是一个动态规划，f[i]=max(f[i-1],0)+a[i]，然后数组可以简化为一个变量。

class Solution {
public:
    int maxSubArray(vector<int>& nums) {
        int sz=nums.size();
        int res=INT_MIN,cur=0;
        for(int i=0;i<sz;i++){
            cur+=nums[i];
            if(cur>res){
                res=cur;
            }
            if(cur<0)cur=0;
        }
        return res;
    }
};