NYoj 部分和问题(深搜经典)

题目链接：

http://acm.nyist.edu.cn/JudgeOnline/problem.php?pid=1058

#include <stdio.h>  
int n, k, ok, arr[22], vis[22], count;  
  
void DFS(int pos){  
        if(count == k)  
        {  
                ok = 1;  
                printf("YES
");  
            for(int i = 0; i < n; ++i)  
                if(vis[i])   
                    printf("%d ", arr[i]);  
            printf("
");  
        }  
      
    for(int i = pos; i < n; ++i)  
    {  
        count += arr[i];  
        vis[i] = 1;  
        DFS(i + 1);  
        count -= arr[i];  
        vis[i] = 0;  
    }  
}  
  
int main(){  
    while(scanf("%d%d", &n, &k) == 2){  
        ok = 0;  
        for(int i = 0; i < n; ++i){  
            scanf("%d", arr[i]);  
            vis[i] = 0;  
        }  
        count = 0; DFS(0);  
        if(!ok) printf("NO
");  
    }  
    return 0;  
}