Submission #543892

#	Time	Username	Problem	Language	Result	Execution time	Memory
543892		Olympia	어르신 집배원 (BOI14_postmen)	C++17	0 / 100	2 ms	340 KiB

postmen

#include <vector>
#include <algorithm>
#include <iostream>
#include <set>
#include <cmath>
#include <map>
#include <random>
#include <cassert>
#include <ctime>
#include <cstdlib>
#include <queue>
#include <limits.h>

using namespace std;

vector<vector<int>> adj;

set<pair<int,int>> invalid;

bool isValid (int u, int v) {
    return !(invalid.count({u, v}));
}

void remove_edge (int u, int v) {
    invalid.insert({u, v}), invalid.insert({v, u});
}

vector<bool> hasVisited;

int main() {
    freopen("balancing.in", "r", stdin);
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    int N, M; cin >> N >> M; adj.resize(N); hasVisited.assign(N, false);
    for (int i = 0; i < M; i++) {
        int u, v; cin >> u >> v; u--, v--;
        adj[u].push_back(v), adj[v].push_back(u);
    }
    vector<pair<int,int>> nodes;
    for (int i = 0; i < N; i++) {
        nodes.push_back({i, i});
        while (!nodes.empty()) {
            int cur = nodes.back().first;
            int prev = nodes.back().second;
            hasVisited[cur] = true;
            bool upd = false;
            for (int j: adj[cur]) {
                if (!isValid(cur, j) || j == prev) {
                    continue;
                }
                if (hasVisited[j]) {
                    vector<int> popped;
                    while (!nodes.empty() && nodes.back().first != j) {
                        hasVisited[nodes.back().first] = false;
                        cout << nodes.back().first + 1 << ' ';
                        //popped.push_back(nodes.back().first);
                        remove_edge(nodes.back().first, nodes.back().second);
                        nodes.pop_back();
                    }
                    remove_edge(nodes.back().first, nodes.back().second);
                    cout << j + 1 << ' ';
                    cout << '\n';
                    /*
                    popped.push_back(j);
                    for (int x = 0; x < popped.size(); x++) {
                        remove_edge(popped[x], popped[(x + 1) % popped.size()]);
                    }
                     */
                } else {
                    nodes.push_back({j, cur});
                }
                upd = true;
                break;
            }
            if (!upd) {
                nodes.pop_back();
            }
        }
    }
}

Compilation message (stderr)

postmen.cpp: In function 'int main()':
postmen.cpp:31:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   31 |     freopen("balancing.in", "r", stdin);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~

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