Submission #948358

#	Time	Username	Problem	Language	Result	Execution time	Memory
948358		vjudge1	Pipes (CEOI15_pipes)	C++17	10 / 100	1526 ms	65536 KiB

pipes

#include <bits/stdc++.h>
using namespace std;
 
//#define int long long
#define pb push_back
#define ff first
#define ss second
#define all(v) v.begin(), v.end()
#define rall(v) v.rbegin(), v.rend()
#define sz(v) (int)v.size()
 
//const int INF = 1e18;
const int mod = 998244353;
const int N = 1e5+5;

int n;
vector<vector<int>> adj;
vector<bool> visited;
vector<int> tin, low;
int timer;
map<pair<int,int>,bool> bridge;

void IS_BRIDGE(int u, int v){
	bridge[{min(u, v), max(u, v)}] = 1;
}

void dfs(int v, int p = -1) {
    visited[v] = true;
    tin[v] = low[v] = timer++;
    for (int to : adj[v]) {
        if (to == p) continue;
        if (visited[to]) {
            low[v] = min(low[v], tin[to]);
        } else {
            dfs(to, v);
            low[v] = min(low[v], low[to]);
            if (low[to] > tin[v])
                IS_BRIDGE(v, to);
        }
    }
}

void find_bridges() {
    timer = 0;
    visited.assign(n, false);
    tin.assign(n, -1);
    low.assign(n, -1);
    for (int i = 0; i < n; ++i) {
        if (!visited[i])
            dfs(i);
    }
}

void solve(){
	cin >> n;
	int m; cin >> m;
	adj.resize(n);
	for(int i = 0; i < m; i++){
		int u, v; cin >> u >> v;
		u--; v--;
		adj[u].pb(v);
		adj[v].pb(u);
	}
	find_bridges();
	for(auto [u, v] : bridge) cout << u.ff + 1 << ' ' << u.ss + 1 << '\n';
}

main(){
	ios_base::sync_with_stdio(0);
	cin.tie(0);
	cout.tie(0);
	
	int tt = 1;
	//cin >> tt;
	while (tt--) {
		solve();
	}
}

Compilation message (stderr)

pipes.cpp:68:1: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
   68 | main(){
      | ^~~~

• Subtask 1: 0 / 10
• Subtask 2: 0 / 10
• Subtask 3: 10 / 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