#pragma GCC optimize("Ofast")
#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using ld = long double;
const int BLOCK = 25000;
const int MAXN = 100000;
vector <pair <int, tuple <int, int, int>>> graf[MAXN+5];
vector <pair <int, tuple <int, int, int>>> ngraf[MAXN+5];
bool visited[MAXN+5];
int in[MAXN+5];
int up[MAXN+5];
int gde[MAXN+5];
int ide[MAXN+5];
int tjm;
void dfs_bridges(int v, int gr){
visited[v] = 1;
in[v] = ++tjm;
up[v] = in[v];
for(auto c : graf[v]){
if(visited[c.first]){
if(get<2>(c.second) == gr) continue;
up[v] = min(up[v], up[c.first]);
}
else{
dfs_bridges(c.first, get<2>(c.second));
up[v] = min(up[v], up[c.first]);
}
}
}
void dfs_connect(int v, tuple <int, int, int> p, int lst){
int sd = lst;
visited[v] = 1;
ide[v] = v;
if(up[v] >= in[v]){
if(lst){
ngraf[v].push_back({lst, p});
swap(get<0>(p), get<1>(p));
ngraf[lst].push_back({v, p});
}
sd = v;
}
else ide[v] = gde[lst];
for(auto c : graf[v]){
if(!visited[c.first]) dfs_connect(c.first, c.second, sd);
}
}
int main(){
ios_base::sync_with_stdio(false), cin.tie(0);
cout.precision(10);
cout << fixed;
int n, m;
cin >> n >> m;
for(int i=1; i<=n; i++){
gde[i] = i;
}
int svih = 0;
while(m > 0){
for(int i=1; i<=min(m, BLOCK); i++){
int a, b;
cin >> a >> b;
++svih;
graf[gde[a]].push_back({gde[b], {a, b, svih}});
graf[gde[b]].push_back({gde[a], {b, a, svih}});
}
tjm = 0;
for(int i=1; i<=n; i++) visited[i] = 0;
for(int i=1; i<=n; i++) ngraf[i].clear();
for(int i=1; i<=n; i++){
if(!visited[gde[i]]) dfs_bridges(gde[i], 0);
}
for(int i=1; i<=n; i++) visited[i] = 0;
for(int i=1; i<=n; i++){
if(!visited[gde[i]]) dfs_connect(gde[i], {0, 0, 0}, 0);
}
for(int i=1; i<=n; i++){
gde[i] = ide[gde[i]];
vector <pair <int, tuple <int, int, int>>>().swap(graf[i]);
for(auto c : ngraf[i]) graf[i].push_back(c);
vector <pair <int, tuple <int, int, int>>>().swap(ngraf[i]);
}
m -= BLOCK;
}
for(int i=1; i<=n; i++){
for(auto c : graf[i]) if(get<0>(c.second) < get<1>(c.second)) cout << get<0>(c.second) << " " << get<1>(c.second) << "\n";
}
return 0;
}
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
3 ms |
4940 KB |
Output is correct |
2 |
Correct |
3 ms |
4940 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
8 ms |
5940 KB |
Output is correct |
2 |
Correct |
8 ms |
5636 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
137 ms |
7876 KB |
Output is correct |
2 |
Correct |
134 ms |
7272 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
222 ms |
8344 KB |
Output is correct |
2 |
Correct |
260 ms |
7148 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
372 ms |
9476 KB |
Output is correct |
2 |
Correct |
418 ms |
10064 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
577 ms |
13016 KB |
Output is correct |
2 |
Correct |
528 ms |
11844 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
886 ms |
14056 KB |
Output is correct |
2 |
Correct |
1446 ms |
12928 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
1234 ms |
15836 KB |
Output is correct |
2 |
Correct |
1210 ms |
14224 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
1503 ms |
16028 KB |
Output is correct |
2 |
Correct |
1447 ms |
14200 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
1828 ms |
15616 KB |
Output is correct |
2 |
Correct |
3473 ms |
14560 KB |
Output is correct |