最大子数组

#include "stdafx.h"struct result{public:    int left, right, sum;};struct result Find_Max_Crossing_Subarray(int a[],int low,int mid,int high){    result cross;    int left_sum = -1000,right_sum = -1000;    int sum = 0;    for (int i = mid; i > low;--i)    {        sum += a[i];        if (sum > left_sum)        {            left_sum = sum;            cross.left = i;        }    }    sum = 0;    for (int i = mid + 1; i < high; ++i)    {        sum += a[i];        if (sum > right_sum)        {            right_sum = sum;            cross.right = i;        }    }    cross.sum = left_sum + right_sum;    return cross;}struct result Find_Maximum_Subarray(int a[], int low, int high){    result max,max_left,max_right,max_cross;    int mid = 0;    if (low == high)    {        max.left = low;        max.right = high;        max.sum = a[high];        return max;    }    else    {        mid = (low + high) / 2;        max_left = Find_Maximum_Subarray(a, low, mid);        max_right = Find_Maximum_Subarray(a, mid + 1, high);        max_cross = Find_Max_Crossing_Subarray(a, low, mid, high);        if (max_left.sum >= max_right.sum && max_left.sum >= max_cross.sum)        {            return max_left;        }        else if (max_right.sum >= max_left.sum && max_right.sum >= max_cross.sum)            return max_right;        else            return max_cross;    }       }int _tmain(int argc, _TCHAR* argv[]){    int a[] = { 13, -3, -25, 20, -3, -16, -23, 18, 20, -7, 12, -5, -22, 15, -4, 7 };    result result_max;    result_max = Find_Maximum_Subarray(a, 0, sizeof(a) / 4 - 1);    cout << result_max.left << endl;    cout << result_max.right << endl;    cout << result_max.sum << endl;    return 0;}