/**
* Sources: various
*/
#pragma GCC optimize("O3")
#pragma GCC target("sse4")
#include <bits/stdc++.h>
#include <ext/pb_ds/tree_policy.hpp>
#include <ext/pb_ds/assoc_container.hpp>
using namespace std;
using namespace __gnu_pbds;
typedef long long ll;
typedef vector<int> vi;
typedef pair<int, int> pii;
template <class T> using Tree = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
#define FOR(i, a, b) for (int i=a; i<(b); i++)
#define F0R(i, a) for (int i=0; i<(a); i++)
#define FORd(i,a,b) for (int i = (b)-1; i >= a; i--)
#define F0Rd(i,a) for (int i = (a)-1; i >= 0; i--)
#define sz(x) (int)(x).size()
#define mp make_pair
#define pb push_back
#define f first
#define s second
#define lb lower_bound
#define ub upper_bound
#define all(x) x.begin(), x.end()
const int MOD = 1000000007;
template<typename T>
ostream& operator<< (ostream& out, const pair<T, T>& v) {
out << "{" << v.first << ", " << v.second << "}";
return out;
}
template<typename T>
ostream& operator<< (ostream& out, const vector<T>& v) {
out << "[";
size_t last = v.size() - 1;
for(size_t i = 0; i < v.size(); ++i) {
out << v[i];
if (i != last)
out << ", ";
}
out << "]";
return out;
}
template<typename T>
ostream& operator<< (ostream& out, const set<T>& v) {
out << "[";
auto pen = v.end();
pen--;
for (auto it = v.begin(); it != v.end(); it++){
out << *it;
if (it != pen){
out << ", ";
}
}
out << "]";
return out;
}
template<typename T>
ostream& operator<< (ostream& out, const Tree<T>& v) {
out << "[";
auto pen = v.end();
pen--;
for (auto it = v.begin(); it != v.end(); it++){
out << *it;
if (it != pen){
out << ", ";
}
}
out << "]";
return out;
}
template<int SZ> struct DSU {
int par[SZ];
DSU() {
F0R(i,SZ) par[i] = i;
}
int get(int x) { // path compression
if (par[x] != x) par[x] = get(par[x]);
return par[x];
}
bool unite(int x, int y) { // union-by-rank
x = get(x), y = get(y);
if (x == y) return 0;
par[y] = x;
return 1;
}
};
DSU<100005> one_connected;
DSU<100005> two_connected;
vector<int> adj[100005];
vector<int> adj2[100005];
map<pii, int> cnt;
int mxlabel[100005];
int mnlabel[100005];
int label[100005];
int sz[100005];
bool vis[100005];
int timer = 1;
void DFS(int v, int p = -1){
//cout << v << ' ' << p << endl;
vis[v] = true;
label[v] = timer++;
sz[v] = 1;
for (int j: adj[v]){
if (j == p) continue;
DFS(j, v);
sz[v] += sz[j];
}
}
void DFS2(int v, int p = -1){
vis[v] = true;
mxlabel[v] = -MOD;
mnlabel[v] = MOD;
for (int j: adj2[v]){
if (j != p){
mxlabel[v] = max(mxlabel[v], label[j]);
mnlabel[v] = min(mnlabel[v], label[j]);
}
}
for (int j: adj[v]){
if (j != p){
DFS2(j, v);
}
}
}
void DFS3(int v, int p = -1){
vis[v] = true;
for (int j: adj[v]){
if (j != p){
DFS3(j, v);
mxlabel[v] = max(mxlabel[v], mxlabel[j]);
mnlabel[v] = min(mnlabel[v], mnlabel[j]);
}
}
}
void DFS4(int v, int p = -1){
vis[v] = true;
for (int j: adj[v]){
if (j != p){
DFS4(j, v);
bool is_bridge = true;
if (mnlabel[j] < label[j]){
is_bridge = false;
}
if (mxlabel[j] >= label[j] + sz[j]){
is_bridge = false;
}
if (is_bridge){
if (j < v) swap(j, v);
if (cnt[make_pair(j, v)] == 1){
cout << j << ' ' << v << endl;
}
}
}
}
}
int main() {
ios_base::sync_with_stdio(0);cin.tie(0);
int n, m; cin >> n >> m;
int u, v;
for (int i = 0; i < m; i++){
cin >> u >> v;
if (!one_connected.unite(u, v)){
if (!two_connected.unite(u, v)){
continue;
}
else{
adj2[u].pb(v);
adj2[v].pb(u);
if (u < v) swap(u, v);
cnt[make_pair(u, v)]++;
}
}
else{
adj[u].pb(v);
adj[v].pb(u);
if (u < v) swap(u, v);
cnt[make_pair(u, v)]++;
}
}
for (int i = 1; i <= n; i++){
if (!vis[i]){
DFS(i);
}
}
memset(vis, false, sizeof(vis));
for (int i = 1; i <= n; i++){
if (!vis[i]){
DFS2(i);
}
}
memset(vis, false, sizeof(vis));
for (int i = 1; i <= n; i++){
if (!vis[i]){
DFS3(i);
}
}
memset(vis, false, sizeof(vis));
for (int i = 1; i <= n; i++){
if (!vis[i]){
DFS4(i);
}
}
return 0;
}
// read!read!read!read!read!read!read!
// ll vs. int!
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Runtime error |
1057 ms |
65536 KB |
Execution killed with signal 9 (could be triggered by violating memory limits) |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Runtime error |
885 ms |
65536 KB |
Execution killed with signal 9 (could be triggered by violating memory limits) |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Correct |
100 ms |
6660 KB |
Output is correct |
| 2 |
Correct |
99 ms |
6632 KB |
Output is correct |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Correct |
171 ms |
7924 KB |
Output is correct |
| 2 |
Incorrect |
195 ms |
7880 KB |
Wrong number of edges |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Correct |
317 ms |
10708 KB |
Output is correct |
| 2 |
Execution timed out |
5063 ms |
44584 KB |
Time limit exceeded |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Runtime error |
626 ms |
20192 KB |
Memory limit exceeded (if you are sure your verdict is not MLE, please contact us) |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Runtime error |
879 ms |
22324 KB |
Memory limit exceeded (if you are sure your verdict is not MLE, please contact us) |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Runtime error |
1164 ms |
26012 KB |
Memory limit exceeded (if you are sure your verdict is not MLE, please contact us) |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Runtime error |
1385 ms |
26012 KB |
Memory limit exceeded (if you are sure your verdict is not MLE, please contact us) |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Runtime error |
1484 ms |
25060 KB |
Memory limit exceeded (if you are sure your verdict is not MLE, please contact us) |
| 2 |
Halted |
0 ms |
0 KB |
- |
