Submission #1153099

#	Time	Username	Problem	Language	Result	Execution time	Memory
1153099		dpsaveslives	Pipes (CEOI15_pipes)	C++20	100 / 100	574 ms	7500 KiB

pipes

#include <bits/stdc++.h>
#define ll long long
using namespace std;
const int MAXN = 1e5+5;
vector<int> adj[MAXN];
mt19937 rnd(time(0));
int N,M,par[MAXN],sz[MAXN],t;
ll val[MAXN];
int finden(int x){
    if(par[x] == x) return x;
    return (par[x] = finden(par[x]));
}
void dfs(int u, int p){
    //cout << u << "\n";
    for(auto v : adj[u]){
        if(v != p){
            dfs(v,u);
            val[u] += val[v];
            //cout << val[v] << "\n";
            if(!val[v]){
                cout << u << " " << v << "\n";
            }
        }
    }
}
/* 10 11
 1 7
 1 8
 1 6
 2 8
 6 7
 5 8
 2 5
 2 3
 2 4
 3 4
 10 9*/
int main()
{
    ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
    cin >> N >> M;
    for(int i = 1;i<=N;++i){
        par[i] = i;
        sz[i] = 1;
    }
    for(int i = 0;i<M;++i){
        int u,v; cin >> u >> v;
        int pu = finden(u), pv = finden(v);
        if(pu != pv){
            if(sz[pu] > sz[pv]) swap(pu,pv);
            sz[pv] += sz[pu]; par[pu] = pv;
            adj[u].push_back(v); adj[v].push_back(u);
        }
        else{
            ll w = rnd();
            val[u] += w; val[v] -= w;
        }
    }
    for(int i = 1;i<=N;++i){
        if(i == par[i]){
            dfs(i,0);
        }
    }
    return 0;
}

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