Submission #547282

#	Time	Username	Problem	Language	Result	Execution time	Memory
547282		Jomnoi	Senior Postmen (BOI14_postmen)	C++17	100 / 100	427 ms	66236 KiB

postmen

#include <bits/stdc++.h>
#define DEBUG 0
using namespace std;
 
const int MAX_N = 5e5 + 10;
 
vector <pair <int, int>> graph[MAX_N];
vector <int> order;
bool used[MAX_N], visited[MAX_N];
 
void dfs(int u) {
    while(!graph[u].empty()) {
        auto [v, i] = graph[u].back();
        graph[u].pop_back();

        if(used[i] == false) {
            used[i] = true;
            dfs(v);
        }
    }
    order.push_back(u);
}
 
int main() {
    cin.tie(0)->sync_with_stdio(0);
    int n, m;
    cin >> n >> m;
    for(int i = 1; i <= m; i++) {
        int u, v;
        cin >> u >> v;
        graph[u].emplace_back(v, i);
        graph[v].emplace_back(u, i);
    }

    dfs(1);

    stack <int> ans;
    for(int i = 0; i < order.size(); i++) {
        if(visited[order[i]] == true) {
            cout << order[i] << ' ';
            while(ans.top() != order[i]) {
                visited[ans.top()] = false;
                cout << ans.top() << ' ';
                ans.pop();
            }
            cout << '\n';
        }
        else {
            visited[order[i]] = true;
            ans.push(order[i]);
        }
    }
    return 0;
}

Compilation message (stderr)

postmen.cpp: In function 'int main()':
postmen.cpp:38:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   38 |     for(int i = 0; i < order.size(); i++) {
      |                    ~~^~~~~~~~~~~~~~

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