36 lines
852 B
Python
36 lines
852 B
Python
import sys
|
|
|
|
input = sys.stdin.readline
|
|
|
|
INF = 1 << 30
|
|
|
|
|
|
def bellman_ford(N, E, start=1):
|
|
dist = [INF] * (N + 1)
|
|
parent = [0] * (N + 1)
|
|
|
|
dist[start] = 0
|
|
for _ in range(1, N + 1):
|
|
for u, v, w in E:
|
|
if dist[u] + w < dist[v]:
|
|
dist[v] = dist[u] + w
|
|
parent[v] = u
|
|
|
|
for u, v, w in E:
|
|
if dist[u] + w < dist[v]:
|
|
return -INF
|
|
return dist[N]
|
|
|
|
|
|
if __name__ == "__main__":
|
|
T = int(input())
|
|
for _ in range(T):
|
|
N, M, W = map(int, input().split())
|
|
E = []
|
|
for s, e, w in [map(int, input().split()) for _ in range(M)]:
|
|
E.append((s, e, w))
|
|
E.append((e, s, w))
|
|
for s, e, w in [map(int, input().split()) for _ in range(W)]:
|
|
E.append((s, e, -w))
|
|
print("YES" if bellman_ford(N, E) < 0 else "NO")
|