Submission #677262

#	Time	Username	Problem	Language	Result	Execution time	Memory
677262		Alma	Senior Postmen (BOI14_postmen)	C++17	0 / 100	1 ms	468 KiB

postmen

#include <bits/stdc++.h>
using namespace std;

int n, m;
bool flag;
vector<vector<int>> adj;
vector<vector<int>> ans;
vector<int> st;
stack<int> path;
set<pair<int, int>> used;

void dfs(int u, int p) {
    if (flag) return;
    st[u] = 1;
    path.push(u);

    for (int v: adj[u]) {
        if (flag) return;
        if (v == p) continue;
        if (used.find({u, v}) != used.end()) continue;

        if (st[v] == 1) { // loop
            vector<int> aux;
            aux.push_back(v);
            int prev = v;

            while (!path.empty() and path.top() != v) {
                int w = path.top();
                // cout << w+1 << '\n';
                used.insert({prev, w});
                used.insert({w, prev});
                aux.push_back(w);
                path.pop();
                prev = w;
            }

            // for (int i = 0; i < (int)aux.size(); i++) {
            //     cout << aux[i]+1 << ' ';
            // }

            used.insert({prev, v});
            used.insert({v, prev});
            ans.push_back(aux);
            flag = true;
            return;

        } else if (st[v] == 0) {
            dfs(v, u);
        }
    }
    st[u] = 2;
    path.pop();
}

int main() {
    ios::sync_with_stdio(false);
    cin.tie(NULL);

    cin >> n >> m;
    adj = vector<vector<int>>(n);

    int u, v;
    while (m--) {
        cin >> u >> v;
        u--;
        v--;
        adj[u].push_back(v);
        adj[v].push_back(u);
    }

    // 0 still not processed
    // 1 in dfs
    // 2 processed
    for (int i = 0; i < n; i++) {
        st = vector<int>(n, 0);
        path = stack<int>();
        flag = false;
        dfs(i, -1);
    }

    for (int i = 0; i < (int)ans.size(); i++) {
        for (int j = 0; j < (int)ans[i].size(); j++) {
            cout << ans[i][j]+1 << ' ';
        }
        cout << '\n';
    }

    return 0;
}

• Subtask 1: 0 / 38
• Subtask 2: 0 / 17
• Subtask 3: 0 / 45