01-复杂度1 最大子列和问题——分而治之

#include<stdio.h>

int DC(int left, int right, int *num)
{
    //已经分到了最小
    if (left==right)
    {
        return num[left];
    }
    
    //分 治
    int mid = (right+left)/2;
    int left_sum = DC(left, mid, num);
    int right_sum = DC(mid+1, right, num);
    

    //判断跨越边界向两边的大小
    int ssum = 0;
    int left_mid_sum = 0;
    for(int i = mid; i>=left; i--)
    {
        ssum += num[i];
        if (ssum>=left_mid_sum)
        {
            left_mid_sum = ssum;
        }
        
    }
    ssum = 0;
    int right_mid_sum = 0;
    for(int i = mid+1; i<=right; i++)
    {
        ssum += num[i];
        if (ssum>=right_mid_sum)
        {
            right_mid_sum = ssum;
        }
    }

    //合
    int sum = left_mid_sum+right_mid_sum;

    if(left_sum>sum) sum = left_sum;
    if(right_sum>sum) sum = right_sum;
    
    
    return sum;
}

int main()
{
    int count = 0;

    while(!scanf("%d", &count));
    int num[count];
    for (int i = 0; i < count; i++)
        while(!scanf("%d",&num[i]));
        
    printf("%d",DC(0,count-1,num));
    
    return 0;
}