53. Maximum Subarray

题目：

Find the contiguous subarray within an array (containing at least one number) which has the largest sum.

For example, given the array [-2,1,-3,4,-1,2,1,-5,4],
the contiguous subarray [4,-1,2,1] has the largest sum = 6.

class Solution {public:    int maxSubArray(int A[], int n) {        int sum=A[0];        int maxsum=A[0];        for(int i=1;i<n;i++){            if(sum<0) sum=0;            sum+=A[i];            maxsum=max(sum,maxsum);        }        return maxsum;    }};