邻接表：
Source Code

Problem: 3259		User: Belldandy
Memory: 184K		Time: 79MS
Language: C		Result: Accepted
Source Code
#include<stdio.h>
#define INF 999999
struct NODE
{
	int x,y,length;
}queue[30000];
int length=0;
int bellman(int n)
{
	int i=0,j=0,k=0,check[600],flag=0,u,v;
	for(i=1;i<=n;i++)
	{
		check[i]=INF;
	}
	check[1]=0;
	for(i=0;i<=n;i++)
	{
		flag=0;
		for(j=0;j<length;j++)
		{
			u=queue[j].x; v=queue[j].y;
			if(check[v]>check[u]+queue[j].length)
			{
				check[v]=check[u]+queue[j].length;
				flag=1;
			}
		}
		if(!flag)
		{
			return 0;
		}
	}
	for(j=0;j<length;j++)
	{
		u=queue[j].x; v=queue[j].y;
		if(check[v]>check[u]+queue[j].length)
		{
			return 1;
		}
	}
	return 0;
}
int main()
{
	int f=0,n=0,m=0,w=0;
	int i=0,s=0,e=0,t=0,j=0;
	scanf("%d",&f);
	while(f--)
	{
		scanf("%d%d%d",&n,&m,&w);
		length=0;
		for(i=0;i<m;i++)
		{
			scanf("%d%d%d",&s,&e,&t);
			queue[length].x=s;
			queue[length].y=e;
			queue[length++].length=t;
			queue[length].x=e;
			queue[length].y=s;
			queue[length++].length=t;
		}
		for(i=0;i<w;i++)
		{
			scanf("%d%d%d",&s,&e,&t);
			queue[length].x=s;
			queue[length].y=e;
			queue[length++].length=-t;
		}
		if(bellman(n))
		{
			printf("YES\n");
		}
		else
		{
			printf("NO\n");
		}
	}
}