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| #include <iostream>
#include <cstring>
using namespace std;
const int N = 200001, M = 200001;
int T;
int n, m, k;
int h[N], e[M], ne[M], idx;
int d[N], q[N];
int pos[N];
struct Edge {
int a, b;
} edge[M];
void add(int a, int b) {
e[idx] = b, ne[idx] = h[a], h[a] = idx++;
}
bool topsort() {
int hh = 0, tt = -1;
for (int i = 1; i <= n; ++i)
if (!d[i])
q[++tt] = i;
while (hh <= tt) {
int t = q[hh++];
for (int i = h[t]; ~i; i = ne[i]) {
int j = e[i];
if (--d[j] == 0)
q[++tt] = j;
}
}
return tt == n - 1;
}
int main() {
scanf("%d", &T);
while (T--) {
scanf("%d%d", &n, &m);
memset(h, -1, (n + 1) * 4);
memset(d, 0, (n + 1) * 4);
idx = k = 0;
while (m--) {
int t, a, b;
scanf("%d%d%d", &t, &a, &b);
if (!t) edge[k++] = {a, b};
else {
add(a, b);
++d[b];
}
}
if (!topsort()) puts("NO");
else {
puts("YES");
for (int i = 1; i <= n; ++i)
for (int j = h[i]; ~j; j = ne[j])
printf("%d %d\n", i, e[j]);
for (int i = 0; i < n; ++i) pos[q[i]] = i;
for (int i = 0; i < k; ++i) {
int a = edge[i].a, b = edge[i].b;
if (pos[a] > pos[b]) swap(a, b);
printf("%d %d\n", a, b);
}
}
}
return 0;
}
|