Submission #109987

#	Time	Username	Problem	Language	Result	Execution time	Memory
109987		someone_aa	Pipes (CEOI15_pipes)	C++17	20 / 100	3832 ms	13132 KiB

pipes

#include <bits/stdc++.h>
#define ll long long
#define pb push_back
#define mp make_pair
using namespace std;
const int maxn = 100100;
vector<int>g[maxn];
int n, m;
int tin[maxn], low[maxn];

int U[2][maxn];

int find(int t, int x){
    return x==U[t][x] ? x : U[t][x]=find(t,U[t][x]);
}
void unite(int t, int x, int y){
    if(find(t,x)==find(t,y)) return;
    U[t][U[t][y]]=U[t][x];
}


int br;
bool visited[maxn];

void dfs(int node, int p) {
    tin[node] = br++;
    low[node] = tin[node];
    visited[node] = true;
    for(int i:g[node]) {
        if(i == p) continue;
        if(visited[i]) {
            low[node] = min(low[node], tin[i]);
        }
        else {
            dfs(i, node);
            low[node] = min(low[node], low[i]);
            if(low[i] > tin[node]) {
                cout<<i<<" "<<node<<"\n";
            }
        }
    }
}

int main() {
    cin>>n>>m;
    int u, v;

    for(int i=1; i<=n; i++) U[0][i]=U[1][i]=i;

    for(int i=1; i<=m; i++){
        int u, v; cin>>u>>v;
        if(find(0,u)==find(0,v)){
            if(find(1,u)==find(1,v)) continue;
            unite(1,u,v);
        }
        else unite(0,u,v);
        g[u].push_back(v);
        g[v].push_back(u);
    }

    for(int i=1;i<=n;i++) {
        if(!visited[i]) {
            dfs(i, -1);
        }
    }

    return 0;
}

Compilation message (stderr)

pipes.cpp: In function 'int main()':
pipes.cpp:46:9: warning: unused variable 'u' [-Wunused-variable]
     int u, v;
         ^
pipes.cpp:46:12: warning: unused variable 'v' [-Wunused-variable]
     int u, v;
            ^

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