#include <bits/stdc++.h>
typedef long long ll;
using namespace std;
int cmp1[100001], cmp2[100001];
vector<int> graph[100001];
bool visited[100001];
int tin[100001], low[100001], timer = 0;
int find(int A, int *cmp) {
while (cmp[A] != A) cmp[A] = cmp[cmp[A]], A = cmp[A];
return A;
}
void onion(int A, int B, int *cmp) {
cmp[find(A, cmp)] = find(B, cmp);
}
void dfs(int node, int parent = 0) {
visited[node] = true;
tin[node] = low[node] = timer++;
sort(graph[node].begin(), graph[node].end());
for (int ptr = 0; ptr < graph[node].size(); ptr++) {
int i = graph[node][ptr];
if (i != parent) {
if (visited[i]) low[node] = min(low[node], tin[i]);
else {
dfs(i, node);
low[node] = min(low[node], low[i]);
if (low[i] > tin[node] && (i + 1 == graph[node].size() || i != graph[node][ptr + 1]) && (!i || i != graph[node][ptr - 1])) cout << node << ' ' << i << '\n';
}
}
}
}
int main() {
ios_base::sync_with_stdio(0);
cin.tie(0);
int n, m;
cin >> n >> m;
iota(cmp1 + 1, cmp1 + n + 1, 1);
iota(cmp2 + 1, cmp2 + n + 1, 1);
while (m--) {
int u, v;
cin >> u >> v;
if (find(u, cmp1) != find(v, cmp1)) {
onion(u, v, cmp1);
graph[u].push_back(v);
graph[v].push_back(u);
} else if (find(u, cmp2) != find(v, cmp2)) {
onion(u, v, cmp2);
graph[u].push_back(v);
graph[v].push_back(u);
}
}
for (int i = 1; i <= n; i++) if (!visited[i]) dfs(i);
return 0;
}
Compilation message
pipes.cpp: In function 'void dfs(int, int)':
pipes.cpp:23:27: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
23 | for (int ptr = 0; ptr < graph[node].size(); ptr++) {
| ~~~~^~~~~~~~~~~~~~~~~~~~
pipes.cpp:30:50: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
30 | if (low[i] > tin[node] && (i + 1 == graph[node].size() || i != graph[node][ptr + 1]) && (!i || i != graph[node][ptr - 1])) cout << node << ' ' << i << '\n';
| ~~~~~~^~~~~~~~~~~~~~~~~~~~~
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
2 ms |
2668 KB |
Output is correct |
2 |
Correct |
2 ms |
2668 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
6 ms |
3436 KB |
Output is correct |
2 |
Correct |
6 ms |
3052 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
107 ms |
8812 KB |
Output is correct |
2 |
Correct |
108 ms |
8428 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
193 ms |
13804 KB |
Output is correct |
2 |
Correct |
208 ms |
14700 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Runtime error |
303 ms |
22124 KB |
Memory limit exceeded |
2 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Runtime error |
426 ms |
33004 KB |
Memory limit exceeded |
2 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Runtime error |
663 ms |
47068 KB |
Memory limit exceeded |
2 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Runtime error |
890 ms |
60480 KB |
Memory limit exceeded |
2 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Runtime error |
1072 ms |
65536 KB |
Memory limit exceeded |
2 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Runtime error |
1286 ms |
65536 KB |
Memory limit exceeded |
2 |
Halted |
0 ms |
0 KB |
- |