#include<bits/stdc++.h>
using namespace std;
//~ #define endl "\n"
typedef long long int ll;
const int MOD = 1e9 + 7;
const int N = 100000;
int cnt = 1;
pair<int, int> id[N], mn[N];
vector<int> adj[N];
int v[N];
bool vis[N];
struct DSU{
void init(int n){
for(int i = 0; i < n; i++) v[i] = -1;
}
int get(int x){return v[x] < 0 ? x : v[x] = get(v[x]);}
bool unite(int x, int y){
x = get(x); y = get(y);
if(x == y) return 0;
if(v[x] > v[y]) swap(x, y);
v[x] += v[y]; v[y] = x;
return 1;
}
};
void DFS(int x){
id[x].first = cnt; cnt++;
for(int node : adj[x]){
if(id[node].first > 0) continue;
DFS(node);
}
id[x].second = cnt; cnt++;
}
void get_ans(int x, int p){
vis[x] = 1;
for(int node : adj[x]){
if(node == p) continue;
get_ans(node, x);
mn[x].first = min(mn[x].first, mn[node].first);
mn[x].second = max(mn[x].second, mn[node].second);
if(!(mn[node].first < id[node].first || mn[node].second > id[node].second)){
cout << node + 1 << " " << x + 1 << endl;
}
}
}
void solve(){
int n, m; cin >> n >> m;
DSU UF; UF.init(n);
vector<int> done;
for(int i = 0; i < m; i++){
int u, v; cin >> u >> v; u--; v--;
if(UF.unite(v, u)) {adj[u].push_back(v); adj[v].push_back(u); done.push_back(i);}
}
for(int i = 0; i < n; i++) id[i] = {0, 0};
for(int i = 0; i < n; i++){
if(id[i].first == 0){
DFS(i);
}
}
rewind(stdin);
cin >> n >> m;
for(int i = 0; i < n; i++) mn[i] = {id[i].first, id[i].second};
int ind = 0;
for(int i = 0; i < m; i++){
int u, v; cin >> u >> v; u--; v--;
if(ind < (int)done.size() && done[ind] == i){
ind++; continue;
}
mn[u].first = min(mn[u].first, id[v].first);
mn[u].second = max(mn[u].second, id[v].second);
mn[v].first = min(mn[v].first, id[u].first);
mn[v].second = max(mn[v].second, id[u].second);
}
for(int i = 0; i < n; i++) vis[i] = 0;
for(int i = 0; i < n; i++){
if(!vis[i]){
get_ans(i, -1);
}
}
}
signed main(){
ios_base::sync_with_stdio(0);
cin.tie(0);
//~ int tt; cin >> tt;
int tt = 1;
for(int t = 1; t <= tt; t++){
solve();
}
}
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
2 ms |
2644 KB |
Output is correct |
2 |
Correct |
1 ms |
2644 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
5 ms |
2900 KB |
Output is correct |
2 |
Correct |
6 ms |
2900 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
153 ms |
2884 KB |
Output is correct |
2 |
Correct |
168 ms |
2868 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
273 ms |
3220 KB |
Output is correct |
2 |
Correct |
308 ms |
3308 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
423 ms |
3996 KB |
Output is correct |
2 |
Correct |
363 ms |
4312 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
594 ms |
6544 KB |
Output is correct |
2 |
Correct |
509 ms |
6576 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
870 ms |
7128 KB |
Output is correct |
2 |
Correct |
876 ms |
7084 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
1086 ms |
8152 KB |
Output is correct |
2 |
Correct |
1082 ms |
8156 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
1376 ms |
8156 KB |
Output is correct |
2 |
Correct |
1406 ms |
8160 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
1788 ms |
7872 KB |
Output is correct |
2 |
Runtime error |
1995 ms |
65536 KB |
Memory limit exceeded |
3 |
Halted |
0 ms |
0 KB |
- |