spfa负环判断

void dfs(int u)
{
    cir[u] = 1;
    for(int i = id[u];~i;i = edge[i].pre)
    {
        if(!cir[edge[i].to])
            dfs(edge[i].to);
    }
}

/*
spfa负环的判断
*/
#include <iostream>
#include <cstdio>
#include <string.h>
#include <queue>
#include <algorithm>
#define inf (1 << 29)
using namespace std;
typedef long long ll;
const int maxn = 600;
const int maxm = 3e3;
int id[maxn],cnt;
struct node{
    int to,cost,pre;
}e[maxm * 2];
int dis[maxn];
int vis[maxn];
int time[maxn];

queue<int> q;
void init()
{
    while(q.size())q.pop();
    memset(time,0,sizeof(time));
    memset(vis,0,sizeof(vis));
    memset(id,-1,sizeof(id));
    cnt = 0;
}
void add(int from,int to,int cost)
{
    e[cnt].to = to;
    e[cnt].cost = cost;
    e[cnt].pre = id[from];
    id[from] = cnt++;
}
int spfa(int s,int n)
{
    for(int i= 0;i <= n;i++)
        dis[i] = inf;
    q.push(s);
    vis[s] = 1;
    time[s] = 1;
    dis[s] = 0;

    while(q.size())
    {
        int now = q.front();
        q.pop();
        vis[now] = 0;
        for(int i = id[now];~i;i = e[i].pre)
        {
            int to = e[i].to;
            int cost = e[i].cost;
            if(dis[to] > dis[now] + cost)
            {
                dis[to] = dis[now] + cost;
                if(!vis[to])
                {
                    vis[to] = 1;
                    q.push(to);
                    if(++time[to] > n)
                        return 0;
                }
            }
        }
    }
    return 1;
}
int main()
{
    int t;
    scanf("%d",&t);
    while(t--)
    {
        int n,m,k;
        scanf("%d%d%d",&n,&m,&k);
        init();
        int a,b,x;
        for(int i = 1;i <= m;i++)
        {
            scanf("%d%d%d",&a,&b,&x);
            add(a,b,x);
            add(b,a,x);
        }
        for(int i = 1;i <= k;i++)
        {
            scanf("%d%d%d",&a,&b,&x);
            add(a,b,-x);
        }
        int op = spfa(1,n);

        if(op)
            printf("NO\n");
        else
            printf("YES\n");
    }
    return 0;
}