题目：

分治法求解思路： 

 

代码： 

#include<iostream>
using namespace std;int maxSum(int arr[], int left, int right)
{int sum = 0;if (left == right){if (arr[left] > 0){return arr[left];}else{return 0;}}else{int center = (left + right) / 2;int leftSum = maxSum(arr, left, center);int rightSum = maxSum(arr, center + 1, right);int s1 = 0;int lefts = 0;for (int i = center; i >= left; i--){lefts += arr[i];if (lefts > s1){s1 = lefts;}}int s2 = 0;int rights = 0;for (int i = center + 1; i <= right; i++){rights += arr[i];if (rights > s2){s2 = rights;}}int s = s1 + s2;int maxx = max(leftSum, s);sum = max(maxx, rightSum);}return sum;
}
int main()
{int arr[] = { 1,5,-2,7,-3,77,-45,-77,100,45,-34,33 };int len = sizeof(arr) / sizeof(int);int maxsum = maxSum(arr, 0, len - 1);cout << maxsum << endl;
}