> 
> //#include<iostream>
> #include<stdio.h>
> #include<algorithm>
> #include<functional>
> using namespace std;
> const int part = 4;
> bool used[30] = {false};
> int len[30];
> int length;
> int find1 = 0;
> int n;
> void dfs(int level,int curlen,int pth);
> void fit(int pth)
> {
> 	if(pth > 4)
> 	{
> 		find1 = 1;
> 	//	cout<<"yes\n";
> 		return ;
> 	}
> 	if(find1) return ;
> 	int i;
> 	for( i = 0 ; i <n ; i++)
> 	{
> 		if(!used[i])
> 			break;
> 	}
> 	used[i] = true;
> 	dfs(i,len[i],pth);
> 	used[i] = false;
> }
> void dfs(int level,int curlen,int pth)
> {
> 	
> 	if(curlen == length )
> 	{
> 		fit(pth+1);
> 		return ;
> 	}
> 	if(level+1> n )
> 		return ;
> 	int i;
> 
> 	for( i = level+1; i<n; i++)
> 	{
> 		if(find1) return ;
> 		if(!used[i])
> 		{
> 			if(curlen+len[i]<=length)
> 			{
> 				used[i] = true;
> 				dfs(i,curlen+len[i],pth);
> 				used[i] = false;
> 			}
> 		}
> 	}
> }
> int main()
> {
> 	int testcase;
> 	int i,j;
> 	int total; 
> //	cin>>testcase;
> 	scanf("%d",&testcase);
> 	for(i =1 ;i<=testcase; i++)
> 	{
> 		total = 0 ;
> 		find1 = 0;
> 	//	cin>>n;
> 		scanf("%d",&n);
> 		for(j = 0 ; j<n; j++)
> 		{
> 		//	cin>>len[j];
> 			scanf("%d",&len[j]);
> 			total +=len[j];
> 		}
> 	    if(total % 4 != 0)
> 			goto output;
> 		length = total/4;
> 		memset(used,false,sizeof(used));
> 		sort(len,len+n,greater<int>());
> 		//if don't add sort it cost 64 ms ,add it 0ms
> 		/*for(j = 0 ; j<n; j++)
> 		{//这个for循环出错了吗？
> 		//	printf("%d ",len[j]);
> 			if(len[j]>length)
> 				goto output;
> 			else if(len[j] == length)
> 			{
> 				if(n != 4)
> 					goto output;
> 			}
> 		}*/
> 		//when adding the cutoff method it go wa 
> 		
> 		fit(1);
> output:
> 		if(find1 == 1) 
> 		//	cout<<"yes\n";
> 		   printf("yes\n");
> 		else //cout<<"no\n";
> 			printf("no\n");
> 	}
> 	return 1;
> }

• 用这个程序生成样例 ，怎么是 NO (192) cxf476 2006-04-17 15:09:00
  • 也许是sticks 太多了 ! (212) cxf476 2006-04-17 15:10:13