using namespace std;
int ufds1[100005],ufds2[100005],low[100005],depths[100005];
vector<int> adj[100005];
int find(int a,int par[]){
if (par[a]==a) return a;
par[a] = find(par[a],par);
return par[a];
}
void dfs(int cur,int par){
depths[cur] = depths[par] + 1;
low[cur] = depths[cur];
bool check= false;
for (auto it: adj[cur]){
if (check == false && it==par){
check = true;
continue;
}
else{
if (depths[it]==-1){
dfs(it,cur);
low[cur] = min(low[cur],low[it]);
if (low[it]>depths[cur]){
cout << cur << ' ' << it << '\n';
}
}else{
low[cur] = min(low[cur],depths[it]);
}
}
}
}
int32_t main(){
ios_base::sync_with_stdio(0);cin.tie(0);
int n,m;cin>>n>>m;
fill(depths,depths+100005,-1);
for (int i=1;i<=n;++i){
ufds1[i] = i;
ufds2[i] = i;
}
for (int i=0;i<m;++i){
int a,b;cin>>a>>b;
int pa = find(a,ufds1), pb = find(b,ufds1);
if (pa!=pb){
adj[a].push_back(b);
adj[b].push_back(a);
ufds1[pb] = pa;
}else{ // it is a back edge
int ba = find(a,ufds2), bb = find(b,ufds2);
if (ba!=bb){
adj[a].push_back(b);
adj[b].push_back(a);
ufds2[bb] = ba;
}
}
}
for (int i=1;i<=n;++i){
if (depths[i]==-1){
dfs(i,0);
}
}
}
//
//4
//4
//2
//2
//2
//4
//4
//4
//4
//2
//4
//4
//2
Compilation message
pipes.cpp:3:1: error: 'vector' does not name a type
3 | vector<int> adj[100005];
| ^~~~~~
pipes.cpp: In function 'void dfs(int, int)':
pipes.cpp:14:19: error: 'adj' was not declared in this scope
14 | for (auto it: adj[cur]){
| ^~~
pipes.cpp:22:24: error: 'min' was not declared in this scope
22 | low[cur] = min(low[cur],low[it]);
| ^~~
pipes.cpp:24:17: error: 'cout' was not declared in this scope
24 | cout << cur << ' ' << it << '\n';
| ^~~~
pipes.cpp:1:1: note: 'std::cout' is defined in header '<iostream>'; did you forget to '#include <iostream>'?
+++ |+#include <iostream>
1 | using namespace std;
pipes.cpp:27:24: error: 'min' was not declared in this scope
27 | low[cur] = min(low[cur],depths[it]);
| ^~~
pipes.cpp: At global scope:
pipes.cpp:34:1: error: 'int32_t' does not name a type
34 | int32_t main(){
| ^~~~~~~
