简化方法其实只用一个数就够了,按照调用的先后顺序,分为旧数和新数

class Solution {
public:
    /**
     * max sum of the subarray
     * @param arr int整型vector the array
     * @return int整型
     */
    int maxsumofSubarray(vector<int>& arr) {
        // write code here



        if(!arr.size()){
            return 0;
        }

        int cur;

        cur = arr[0];
        int max_sum = cur;
        for(int i = 1; i< arr.size();++i){

            cur = max(cur,0) + arr[i];
            max_sum = max(max_sum,cur);

        }

        return max_sum;




    }
};