#include <bits/stdc++.h>
using namespace std;
const int N = 1e5 + 10;
int par1[N], par2[N], h[N], mnh[N], edges;
bool vis[N];
vector<pair<int, int>> g[N];
int root1(int v){
return (par1[v] == -1 ? v : par1[v] = root1(par1[v]));
}
int root2(int v){
return (par2[v] == -1 ? v : par2[v] = root2(par2[v]));
}
void merge1(int u, int v){
int r1 = root1(v);
int r2 = root1(u);
par1[r1] = r2;
edges++;
g[v].push_back({u, edges});
g[u].push_back({v, edges});
}
void merge2(int u, int v){
int r1 = root2(u);
int r2 = root2(v);
if (r1 == r2)
return;
par2[r1] = r2;
edges++;
g[v].push_back({u, edges});
g[u].push_back({v, edges});
}
void dfs(int v, pair<int, int> prev = {-1, -1}){
vis[v] = 1;
if (prev.first == -1)
h[v] = 0;
mnh[v] = h[v];
for (auto [u, id] : g[v]){
if (prev.first == u and prev.second == id)
continue;
mnh[v] = min(mnh[v], h[u]);
if (vis[u])
continue;
h[u] = h[v] + 1;
dfs(u, {v, id});
mnh[v] = min(mnh[v], mnh[u]);
if (mnh[u] >= h[u])
printf("%d %d\n", u, v);
}
}
int main(){
ios_base::sync_with_stdio(0);
cin.tie(0); cout.tie(0);
int n, m;
scanf("%d%d", &n, &m);
for (int i=1; i<=n; i++){
par1[i] = par2[i] = -1;
mnh[i] = n + 100;
h[i] = n + 100;
}
for (int i=0; i<m; i++){
int u, v;
scanf("%d%d", &u, &v);
if (root1(u) != root1(v))
merge1(u, v);
else if (root2(u) != root2(v))
merge2(u, v);
}
for (int v = 1; v <= n; v++)
if (!vis[v])
dfs(v);
}
Compilation message
pipes.cpp: In function 'int main()':
pipes.cpp:72:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
72 | scanf("%d%d", &n, &m);
| ~~~~~^~~~~~~~~~~~~~~~
pipes.cpp:82:14: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
82 | scanf("%d%d", &u, &v);
| ~~~~~^~~~~~~~~~~~~~~~
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
1 ms |
2648 KB |
Output is correct |
2 |
Correct |
1 ms |
2648 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
4 ms |
3420 KB |
Output is correct |
2 |
Correct |
3 ms |
3164 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
72 ms |
3104 KB |
Output is correct |
2 |
Correct |
70 ms |
3096 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
118 ms |
3924 KB |
Output is correct |
2 |
Correct |
138 ms |
3564 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
204 ms |
5892 KB |
Output is correct |
2 |
Correct |
168 ms |
5308 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
278 ms |
12388 KB |
Output is correct |
2 |
Correct |
250 ms |
8612 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
413 ms |
13516 KB |
Output is correct |
2 |
Correct |
392 ms |
9808 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
581 ms |
16180 KB |
Output is correct |
2 |
Correct |
536 ms |
11144 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
665 ms |
15964 KB |
Output is correct |
2 |
Runtime error |
657 ms |
64080 KB |
Memory limit exceeded |
3 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
803 ms |
15252 KB |
Output is correct |
2 |
Runtime error |
850 ms |
65536 KB |
Memory limit exceeded |
3 |
Halted |
0 ms |
0 KB |
- |