1 #include<iostream>
2 #include<cstdio>
3 #include<cstring>
4 using namespace std;
5
6 const int INF = 0x3f3f3f3f;
7 const int maxn = 50005;
8 int n, w, m, k, dis[maxn];
9
10 struct node
11 {
12 int u, v, w;
13 node() {}
14 node(int uu, int vv, int ww): u(uu), v(vv), w(ww) {}
15 }edge[maxn];
16
17 bool Bellman_Ford(int s)
18 {
19 for(int i = 1; i <= n; i++) dis[i] = INF;
20 dis[s] = 0;
21 for(int i = 0; i < n; i++)
22 {
23 int flag = 1;
24 for(int j = 0; j < k; j++)
25 {
26 int u = edge[j].u;
27 int v = edge[j].v;
28 int w = edge[j].w;
29 if(dis[u] + w < dis[v])
30 {
31 flag = 0;
32 dis[v] = dis[u]+w;
33 if(i == n-1)
34 return true;
35 //如果循环n-1次还能缩，就存在负环
36 }
37 }
38 if(flag) return false;
39 }
40 return false;
41 }
42
43 int main()
44 {
45 ios::sync_with_stdio(false);
46 cin.tie(0);
47
48 int t;
49 cin >> t;
50 while(t--)
51 {
52 k = 0;
53 scanf("%d%d%d", &n, &m, &w);
54 for(int i = 1; i <= m+w; i++)
55 {
56 int u, v, w;
57 scanf("%d%d%d", &u, &v, &w);
58 if(i <= m)
59 {
60 edge[k++] = node(u, v, w);
61 edge[k++] = node(v, u, w);
62 }
63 else edge[k++] = node(u, v, -w);
64 }
65 if(Bellman_Ford(1)){
66 cout << "YES" << endl;
67 }
68 else
69 cout << "NO" << endl;
70 }
71 return 0;
72 }
