#include <stdio.h>#define maxn 10000#define INF 0x7f7f7f7fint n,m,c;struct arr{ int x,y,w;}edge[maxn];int d[maxn];int ford(int x){ int fl=0; for (int i=1;i<=n;i++) d[i]=INF; d[1]=0; for (int i=1;i<=n-1;i++) { fl=1; for (int j=1;j<=x;j++) { if (d[edge[j].x]>d[edge[j].y]+edge[j].w) { d[edge[j].x]=d[edge[j].y]+edge[j].w; fl=0; } } if (fl) break; } for (int i=1;i<=x;i++) if (d[edge[i].x]>d[edge[i].y]+edge[i].w) return 0; return 1;}int main(){ int t; scanf("%d",&t); for (int k=1;k<=t;k++) { scanf("%d%d%d",&n,&m,&c); for (int i=1;i<=m+c;i++) edge[i]=(arr){0,0,0}; int l=0; for (int i=1;i<=m;i++) { int x,y,z; scanf("%d%d%d",&x,&y,&z); edge[++l]=(arr){x,y,z}; edge[++l]=(arr){y,x,z}; } for (int i=1;i<=c;i++) { int x,y,z; scanf("%d%d%d",&x,&y,&z); edge[++l]=(arr){x,y,-z}; } if (ford(l)) PRintf("NO/n"); else printf("YES/n"); }}
