Submission #1261470

#	Time	Username	Problem	Language	Result	Execution time	Memory
1261470		antonn	Pipes (CEOI15_pipes)	C++17	70 / 100	565 ms	17820 KiB

pipes

#include <bits/stdc++.h>

using namespace std;

typedef long long ll;

const int N = 1e5 + 7;

int n, m;
vector<int> g[N];
int low[N], tin[N];
bool vis[N];
int tt;

struct Dsu {
    int t[N];
    
    int root(int x) {
        if (t[x] == x) return x;
        return t[x] = root(t[x]);
    }
    
    void merge(int a, int b) {
        a = root(a);
        b = root(b);
        if (a != b) t[b] = a;
    }
    
    bool same(int u, int v) {
        return root(u) == root(v);
    }
    
    Dsu() {
        for (int i = 0; i < N; ++i) t[i] = i;
    }
} dsu1, dsu2;

void dfs(int u, int p = -1) {
    vis[u] = 1;
    tin[u] = ++tt;
    low[u] = tin[u]; 
    for (auto v : g[u]) {
        if (v == p) continue;
        if (vis[v]) {
            low[u] = min(low[u], tin[v]);
        } else {
            dfs(v, u);
            low[u] = min(low[u], low[v]);
            if (low[v] > tin[u] && !dsu2.same(u, v)) cout << u << " " << v << "\n";
        }
    }
}

int main() {
    ios::sync_with_stdio(false);
    cin.tie(0);
    cin >> n >> m;
    int a, b;
    for (int i = 1; i <= m; ++i) {
        cin >> a >> b;
        if (dsu1.same(a, b) && dsu2.same(a, b)) continue;
        g[a].push_back(b);
        g[b].push_back(a);
        if (dsu1.same(a, b)) {
            dsu2.merge(a, b);
        } else {
            dsu1.merge(a, b);
        }
    }
    for (int i = 1; i <= n; ++i) if (!vis[i]) dfs(i);
    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: 0 / 10
• Subtask 9: 0 / 10
• Subtask 10: 0 / 10