#include<bits/stdc++.h>
using namespace std;
#define pb push_back
const int lim=1e5+1;
int parent[lim];
int find(int i){
if(i==parent[i])return i;
return parent[i]=find(parent[i]);
}
void unite(int i,int j){
i=find(i),j=find(j);
parent[i]=j;
}
struct vec{
int*targ=new int[2],size=2,have=0;
void pb(int t){
if(have==size){
int*newy=new int[int(size*2)];
for(int i=0;i<size;i++)newy[i]=targ[i];
size*=2;
delete targ;
targ=newy;
}
targ[have++]=t;
}
void clear(){
have=0;
size=2;
delete targ;
targ=new int[2];
}
};
vec v[lim];
vector<pair<int,int>>edges;
int tin[lim],tout[lim],tt=1;
int dfs(int node,int par){
if(tin[node])return tin[node];
tout[node]=tin[node]=tt++;
for(int i=0;i<v[node].have;i++){
int j=v[node].targ[i];
if(j==par)continue;
if(tin[j]){
tout[node]=min(tout[node],tin[j]);
unite(node,j);
}else{
int res=dfs(j,node);
if(res<=tin[node]){
unite(node,j);
}
tout[node]=min(tout[node],res);
}
}
return tout[node];
}
int n,m;
void findans(){
for(int i=0;i<=n;i++)v[i].clear();
for(auto[x,y]:edges){
v[find(x)].pb(find(y));
v[find(y)].pb(find(x));
}
for(int i=0;i<=n;i++){
tout[i]=tin[i]=0;
}
tt=1;
for(int i=1;i<=n;i++){
if(!tin[i])dfs(i,0);
}
for(int i=0;i<edges.size();i++){
if(find(edges[i].first)==find(edges[i].second)){
swap(edges[i],edges.back());
edges.pop_back();
i--;
}
}
}
int main(){
cin>>n>>m;
for(int i=1;i<=n;i++)parent[i]=i;
for(int i=0;i<m;i++){
int x,y;
cin>>x>>y;
if(find(x)!=find(y))edges.pb({x,y});
if(edges.size()==150000)findans();
}
findans();
for(auto[x,y]:edges)cout<<x<<' '<<y<<'\n';
}
Compilation message
pipes.cpp: In function 'void findans()':
pipes.cpp:76:16: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
76 | for(int i=0;i<edges.size();i++){
| ~^~~~~~~~~~~~~
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
5 ms |
5712 KB |
Output is correct |
2 |
Correct |
4 ms |
5712 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
8 ms |
6220 KB |
Output is correct |
2 |
Correct |
8 ms |
5968 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
172 ms |
9756 KB |
Output is correct |
2 |
Correct |
164 ms |
9664 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
311 ms |
10432 KB |
Output is correct |
2 |
Correct |
350 ms |
9664 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
488 ms |
10940 KB |
Output is correct |
2 |
Correct |
403 ms |
10684 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
636 ms |
14228 KB |
Output is correct |
2 |
Correct |
532 ms |
10860 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
956 ms |
14272 KB |
Output is correct |
2 |
Correct |
932 ms |
12308 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
1260 ms |
13848 KB |
Output is correct |
2 |
Correct |
1128 ms |
10688 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
1491 ms |
13712 KB |
Output is correct |
2 |
Correct |
1482 ms |
10688 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
1967 ms |
14272 KB |
Output is correct |
2 |
Runtime error |
1871 ms |
29376 KB |
Memory limit exceeded |
3 |
Halted |
0 ms |
0 KB |
- |