> #include<stdio.h>
> #include<stdlib.h>
> #include<string.h>
> int a[16];
> int status[16];
> int ca,M,sum,ave,flag;
> 
> int cmp(const void* a,const void* b)
> {
> 	return(*(int*)a-*(int*)b);
> }
> 
> void DFS(int st,int now,int edge)
> {
> 	if(edge==3)
> 	{
> 		flag=1;
> 		return;
> 	}
> 	else if(!flag)
> 	{
> 		int i;
> 		for(i=st;i>=0&&!flag;i--)
> 		{
> 			if(!status[i])
> 			{
> 				if(now+a[i]==ave)
> 				{
> 					status[i]=1;
> 					DFS(M-1,0,edge+1);
> 					status[i]=0;
> 				}
> 				else if(now+a[i]<ave)
> 				{
> 					status[i]=1;
> 					DFS(i,now+a[i],edge);
> 					status[i]=0;
> 				}
> 			}
> 		}
> 	}
> }
> 
> void main()
> {
> 	scanf("%d",&ca);
> 	while(ca--)
> 	{
> 		int i;
> 		sum=0;
> 		memset(status,0,sizeof(status));
> 		scanf("%d",&M);
> 		for(i=0;i<M;i++)
> 		{
> 			scanf("%d",&a[i]);
> 			sum+=a[i];
> 		}
> 		if(sum%4)
> 		{
> 			printf("no\n");
> 			continue;
> 		}
> 		ave=sum/4;
> 		qsort(a,M,sizeof(int),cmp);
> 		if(a[M-1]>ave)
> 		{
> 			printf("no\n");
> 			continue;
> 		}
> 		flag=0;
> 		DFS(M-1,0,0);
> 		if(flag)
> 			printf("yes\n");
> 		else
> 			printf("no\n");
> 	}
> }

• Re:大家帮忙看看我的为什么老是WA,郁闷中....... (24) ccnuzhang 2008-03-16 15:49:53