#include <bits/stdc++.h>
#define ff first
#define ss second
#define pb push_back
#define all(x) x.begin(),x.end()
#define rall(x) x.rbegin(),x.rend()
#define rnd(l, r) uniform_int_distribution<int>(l, r)(rng)
using namespace std;
const int N = 10000 + 2;
int16_t tin[N], tout[N];
int16_t low[N];
bool used[N];
vector <int16_t> g[N];
int16_t timer;
struct hash_pair {
template <class T1, class T2>
size_t operator()(const pair<T1, T2>& p) const
{
auto hash1 = hash<T1>{}(p.first);
auto hash2 = hash<T2>{}(p.second);
if (hash1 != hash2) {
return hash1 ^ hash2;
}
// If hash1 == hash2, their XOR is zero.
return hash1;
}
};
unordered_map <int16_t,int16_t> mp[N], cant[N];
//unordered_map<pair<int, int>, bool, hash_pair> mp, cant;
int n;
int32_t m;
void dfs_low(int16_t v, int16_t p = -1){
used[v] = true;
tin[v] = low[v] = ++timer;
for (auto u : g[v]){
if (u == p) continue;
if (used[u]){
low[v] = min(low[v], tin[u]);
}else{
dfs_low(u, v);
low[v] = min(low[v], low[u]);
if (low[u] > tin[v] && !cant[min(v, u)].count(max(v, u))){
cout << min(v, u) <<" "<< max(v, u) << "\n";
}
}
}
}
main(){
iostream::sync_with_stdio(false);
cin.tie(nullptr);
cout.tie(nullptr);
cin >> n >> m;
for(int i = 0; i < m; i++){
int16_t a, b;
cin >> a >> b;
if(a > b)swap(a, b);
if(mp[a].count(b)){
cant[a][b] = 1;
continue;
}
g[a].pb(b);
g[b].pb(a);
mp[a][b] = 1;
}
for(int i = 1; i <= n; i++){
if(!used[i]){
dfs_low(i);
}
}
}
/*
* Before implementing the problem:
Do I understand the problem correctly?
Which places are tricky? What do I need to remember to implement them correctly?
Which place is the heaviest by implementation? Can I do it simpler?
Which place is the slowest? Where do I need to be careful about constant factors and where I can choose slower but simpler implementation?
----------------------------------
If not AC:
Did you remember to do everything to handle the tricky places you thought about before?
Is the solution correct?
Do I understand the problem correctly?
----------------------------------
If you have a test on which the solution gives wrong answer:
Is the solution doing what it was supposed to do?
Is the problem in the code or in the idea?
*/
Compilation message
pipes.cpp:57:1: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
57 | main(){
| ^~~~
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Correct |
1 ms |
1628 KB |
Output is correct |
| 2 |
Correct |
1 ms |
1628 KB |
Output is correct |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Correct |
5 ms |
2908 KB |
Output is correct |
| 2 |
Correct |
5 ms |
2652 KB |
Output is correct |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Runtime error |
353 ms |
31832 KB |
Memory limit exceeded |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Runtime error |
662 ms |
52068 KB |
Memory limit exceeded |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Runtime error |
2 ms |
3164 KB |
Execution killed with signal 11 |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Runtime error |
2 ms |
3164 KB |
Execution killed with signal 11 |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Runtime error |
2 ms |
3164 KB |
Execution killed with signal 11 |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Runtime error |
2 ms |
3164 KB |
Execution killed with signal 11 |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Runtime error |
2 ms |
3164 KB |
Execution killed with signal 11 |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Runtime error |
2 ms |
3164 KB |
Execution killed with signal 11 |
| 2 |
Halted |
0 ms |
0 KB |
- |
