【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.

题解：简单题，可以用动态规划也可以直接求出本质上一样只是dp的非递归版，刚开始出错是因为遍历dp时用for-each结果dp长度不是本身长度所以出错了，以后对数组用这种遍历时注意长度问题

class Solution {
public:
    int maxSubArray(vector<int>& nums) {
        int maxSub=nums[0];
        int n=nums.size();
        int dp[n];
        dp[0]=nums[0];
        for(int i=1;i<n;i++){
            if(nums[i-1]>0) nums[i]+=nums[i-1];
            if(maxSub<nums[i]) maxSub=nums[i];
        }
        
        return maxSub;
    }
    int DP(vector<int>& nums,int k,int dp[]){
        if(k==0) return nums[0];
        dp[k]=max(DP(nums,k-1,dp),0)+nums[k];
        return dp[k];
    }


};