#include <bits/stdc++.h>
using namespace std;
#define pb push_back
#define sz size
const int mxN = 1e5;
vector<int> adj[mxN];
//int d[mxN];
//int low[mxN];
int p[mxN][2];
int ss[mxN][2];
void dfs(int c, int depth, int par){
p[c][0] = depth;
p[c][1] = depth;
int op = par;
for (int i : adj[c]){
if (i == par){par = -1; continue;}
if (p[i][0] != -1){ p[c][1] = min(p[c][1],p[i][0]); continue;}
dfs(i,depth+1,c);
p[c][1] = min(p[c][1], p[i][1]);
}
if (p[c][1]>= depth && op != -1) cout << c+1 << " " << op+1 << '\n';
}
int gpar(int c, int w){
if (p[c][w] == c) return c;
p[c][w] = gpar(p[c][w],w);
return p[c][w];
}
int main() {
ios_base::sync_with_stdio(false);
cin.tie(NULL);
int n,m;
cin >> n >> m;
for (int i = 0; i < n; i++) for (int j = 0; j < 2; j++) {p[i][j] = i; ss[i][j] = 1;}
int a,b;
int x,y;
int cnt = 0;
for (int i = 0; i < m; i++){
cin >> a >> b;
a -= 1;
b -= 1;
x = gpar(a,0);
y = gpar(b,0);
if (x != y){
adj[a].pb(b);
adj[b].pb(a);
cnt++;
if (ss[x][0] < ss[y][0]) swap(x,y);
ss[x][0] += ss[y][0];
p[y][0] = x;
continue;
}
x = gpar(a,1);
y = gpar(b,1);
if (x == y) continue;
if (ss[x][1] < ss[y][1]) swap(x,y);
ss[x][1] += ss[y][1];
p[y][1] = x;
adj[a].pb(b);
adj[b].pb(a);
cnt++;
}
for (int i = 0; i < n; i++) p[i][0] = -1;
for (int i = 0; i < n; i++) if (p[i][0] == -1) dfs(i,0,-1);
return 0;
}
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
1 ms |
2652 KB |
Output is correct |
2 |
Correct |
2 ms |
2652 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
4 ms |
3416 KB |
Output is correct |
2 |
Correct |
4 ms |
3080 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
61 ms |
8532 KB |
Output is correct |
2 |
Correct |
60 ms |
8276 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
105 ms |
13396 KB |
Output is correct |
2 |
Correct |
124 ms |
14672 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Runtime error |
169 ms |
21532 KB |
Memory limit exceeded |
2 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Runtime error |
299 ms |
31116 KB |
Memory limit exceeded |
2 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Runtime error |
362 ms |
44372 KB |
Memory limit exceeded |
2 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Runtime error |
491 ms |
57172 KB |
Memory limit exceeded |
2 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Runtime error |
605 ms |
65536 KB |
Memory limit exceeded |
2 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Runtime error |
735 ms |
65536 KB |
Memory limit exceeded |
2 |
Halted |
0 ms |
0 KB |
- |