Submission #839590

#	Time	Username	Problem	Language	Result	Execution time	Memory
839590		kyaruru	Pipes (CEOI15_pipes)	C++17	0 / 100	1447 ms	65536 KiB

pipes

#include <bits/stdc++.h>

using namespace std;
typedef long long ll;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;

vector<int> adj[100001];
vector<int> tin(100001,-1),low(100001,-1);
vector<pii> ans;
bool vi[100001];
int t=0;


void dfs(int x,int p=-1){
    vi[x]=true;
    tin[x]=low[x]=t++;
    for(int u:adj[x]){
        if(u==p) continue;
        if(vi[u]){
            low[x]=min(low[x],tin[u]);
        }else{
            dfs(u,x);
            low[x]=min(low[x],low[u]);
            if(low[u]>tin[x]) ans.push_back({min(u,x),max(u,x)});
        }
    }
}

int main() {
    ios::sync_with_stdio(0);
    cin.tie(0);

    int a,b;
    cin>>a>>b;

    for(int i=0; i<b; i++){
        int x,y;
        cin>>x>>y;
        adj[x].push_back(y);
        adj[y].push_back(x);
    }

    for(int i=1; i<=a; i++){
        if(!vi[i]) dfs(i);
    }
    sort(ans.begin(), ans.end());
    cout<<ans.size()<<"\n";
    for(pii u:ans) cout<<u.first<<" "<<u.second<<"\n";
}

• Subtask 1: 0 / 10
• Subtask 2: 0 / 10
• Subtask 3: 0 / 10
• Subtask 4: 0 / 10
• Subtask 5: 0 / 10
• Subtask 6: 0 / 10
• Subtask 7: 0 / 10
• Subtask 8: 0 / 10
• Subtask 9: 0 / 10
• Subtask 10: 0 / 10