> #include<stdio.h>
> #define MAX 1000000
> int n;
> int val[10001];
> int g[5001][5001];
> int Bellman()
> {
> 	int i,j,k;
> 	bool flag;
> //	memset(val,MAX,sizeof(val));
> 	for(i = 1;i <= n;i++) val[i] = MAX;
> 	val[1] = 0;
> 	for(k = 1;k < n;k++)
> 	{
> 		flag = 0;
> 		for(i = 1;i <= n;i++)
> 		{
> 			for(j = 1;j <= n;j++)
> 			{
> 				if(g[i][j] && val[j] > val[i] + g[i][j])
> 				{
> 					val[j] = val[i] + g[i][j];
> 					flag = 1;
> 				}
> 			}
> 		}
> 		if(!flag) break;
> 		//	return 0;
> 	}
> //	printf("flag = %d\n",flag);
> 	for(i = 1;i <= n;i++)
> 	{
> 		for(j = 1;j <= n;j++)
> 		{
> 			if(g[i][j] && val[j] > val[i] + g[i][j])
> 				return 1;
> 		}
> 	}
> 	return 0;
> }
> 
> int main()
> {
> 	int i,j,t,m,w,s,e,d;
> 	scanf("%d",&t);
> 	while(t--)
> 	{
> 		scanf("%d%d%d",&n,&m,&w);
> 		for(i = 1;i <= n;i++)
> 			for(j = 1;j <= n;j++)
> 				g[i][j] = 0;
> 		for(i = 1;i <= m;i++)
> 		{
> 			scanf("%d%d%d",&s,&e,&d);
> 			g[s][e] = d;
> 			g[e][s] = d;
> 		}
> 		for(i = 1;i <= w;i++)
> 		{
> 			scanf("%d%d%d",&s,&e,&d);
> 			g[s][e] = -1*d;
> 		}
> 		if(Bellman())
> 			printf("YES\n");
> 		else
> 			printf("NO\n");
> 	}
> 	return 0;
> }
> /*
> Sample Input
> 2
> 3 3 1
> 1 2 2
> 1 3 4
> 2 3 1
> 3 1 3
> 3 2 1
> 1 2 3
> 2 3 4
> 3 1 8
> Sample Output
> 
> NO
> YES
> */