POJ 3259

#include<iostream>

#include<string>

#include<cstdio>

#include<cstring>

#include<cstdlib>

#include<algorithm>

#include<cmath>

#include<vector>

#include<map>

#define MAXN 10005

#define MAXM 10005

#define MOD 10000

#define inf 1500000000

#define eps 1e-9

#define pi acos(-1.0)

typedef long long LL;

using namespace std;

int T, n, m, w, s, e, t, dis[505];

struct Edge {

int u, v, w, next;

} edge[MAXN];

int es;

void add(int u, int v, int w) {

edge[es].u = u, edge[es].v = v, edge[es].w = w;

}

bool Bellman_Ford() {

for (int i = 1; i <= n; i++) dis[i] = inf;

dis[1] = 0;

bool flag;

for (int i = 1; i < n; i++) {

flag = false;

for (int j = 0; j < es; j++) {

int u = edge[j].u, v = edge[j].v, w = edge[j].w;

if (dis[u] + w < dis[v])

dis[v] = dis[u] + w;

flag = true;

}

if (!flag) return false;

}

for (int i = 0; i < es; i++) {

int u = edge[i].u, v = edge[i].v, w = edge[i].w;

if (dis[u] + w < dis[v]) {

return true;

}

}

return false;

}

int main() {

//freopen("in.txt", "r", stdin);

//freopen("out.txt", "w", stdout);

scanf("%d", &T);

while (T--) {

scanf("%d %d %d", &n, &m, &w);

es = 0;

for (int i = 0; i < m; i++) {

scanf("%d %d %d", &s, &e, &t);

add(s, e, t); es++;

add(e, s, t); es++;

}

for (int i = 0; i < w; i++) {

scanf("%d %d %d", &s, &e, &t);

add(s, e, -t); es++;

}

if (Bellman_Ford()) puts("YES");

else puts("NO");

}

    return 0;

}