#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];
void dfs(int c, int depth, int p){
d[c] = depth;
low[c] = d[c];
int op = p;
for (int i : adj[c]){
if (i == p){p = -1; continue;}
if (d[i] != -1){ low[c] = min(low[c],d[i]); continue;}
dfs(i,depth+1,c);
low[c] = min(low[c], low[i]);
}
if (low[c] >= depth && op != -1) cout << c+1 << " " << op+1 << '\n';
}
int p[mxN][2];
int ssize[mxN][2];
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; ssize[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 (ssize[x][0] < ssize[y][0]) swap(x,y);
ssize[x][0] += ssize[y][0];
p[y][0] = x;
continue;
}
x = gpar(a,1);
y = gpar(b,1);
if (x == y) continue;
if (ssize[x][1] < ssize[y][1]) swap(x,y);
ssize[x][1] += ssize[y][1];
p[y][1] = x;
adj[a].pb(b);
adj[b].pb(a);
cnt++;
}
if (cnt > 2*n-2) while(true) continue;
for (int i = 0; i < n; i++) d[i] = -1;
for (int i = 0; i < n; i++) if (d[i] == -1) dfs(i,0,-1);
return 0;
}
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
2 ms |
2652 KB |
Output is correct |
2 |
Correct |
2 ms |
2676 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
3 ms |
3416 KB |
Output is correct |
2 |
Correct |
3 ms |
3164 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
65 ms |
8496 KB |
Output is correct |
2 |
Correct |
92 ms |
7932 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
108 ms |
12816 KB |
Output is correct |
2 |
Correct |
126 ms |
13904 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Runtime error |
189 ms |
20052 KB |
Memory limit exceeded |
2 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Runtime error |
263 ms |
29552 KB |
Memory limit exceeded |
2 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Runtime error |
386 ms |
41900 KB |
Memory limit exceeded |
2 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Runtime error |
507 ms |
53556 KB |
Memory limit exceeded |
2 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Runtime error |
645 ms |
64136 KB |
Memory limit exceeded |
2 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Runtime error |
820 ms |
65536 KB |
Memory limit exceeded |
2 |
Halted |
0 ms |
0 KB |
- |