Submission #117656

#	Time	Username	Problem	Language	Result	Execution time	Memory
117656		minhtung0404	Pipes (CEOI15_pipes)	C++17	70 / 100	3724 ms	65536 KiB

pipes

//https://oj.uz/problem/view/CEOI15_pipes

#include<bits/stdc++.h>
const int N = 1e5 + 5;
using namespace std;

typedef pair <int, int> ii;
vector <ii> G[N];
int n, m, low[N], num[N], cnt;

struct dsu{
    int pset[N];

    void init(){
        for (int i = 1; i <= n; i++) pset[i] = i;
    }

    int find(int i) {return ((pset[i] == i) ? i : pset[i] = find(pset[i]));}

    bool Union(int i, int j, int id){
        int u = find(i), v = find(j);
        if (u == v) return false;
        pset[u] = v;
        G[i].push_back(ii(j, id));
        G[j].push_back(ii(i, id));
        return true;
    }
} a[2];

void dfs(int u, int p, int id){
    num[u] = low[u] = ++cnt;
    for (auto pr : G[u]){
        int v = pr.first, x = pr.second;
        if (x == id) continue;
        if (num[v]){
            low[u] = min(low[u], num[v]);
        }
        else{
            dfs(v, u, x);
            low[u] = min(low[u], low[v]);
        }
    }
    if (u != p && low[u] >= num[u]) cout << u << " " << p << "\n";
}

int main(){
    cin >> n >> m;
    a[0].init(); a[1].init();
    int u, v;
    for (int i = 1; i <= m; i++){
        cin >> u >> v;
        if (!a[0].Union(u, v, i)) a[1].Union(u, v, i);
    }
    for (int i = 1; i <= n; i++) if (!num[i]) dfs(i, i, 0);
}

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