Submission #861242

#	Time	Username	Problem	Language	Result	Execution time	Memory
861242		qwusha	Senior Postmen (BOI14_postmen)	C++17	0 / 100	24 ms	1796 KiB

postmen

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
#define fi first
#define se second
typedef long double ld;
const ll inf = 1e9;
const ld eps = 1e-8;
vector<map<int, int>> cing;
vector<set<int>> g;
vector<vector<int>> ans;
vector<bool> used;
vector<int> cur;
set<pair<int, int>> vert;

void dfs(int v) {
    used[v] = 1;
    cur.push_back(v);
    for (auto u : g[v]) {
        if (vert.find({v, u}) == vert.end()) {
            continue;
        }
        vert.erase({v, u});
        vert.erase({u, v});
        if (used[u]) {
            vector<int> res;
            while(!cur.empty() && cur.back() != u) {
                res.push_back(cur.back());
                used[cur.back()] = 0;
                cur.pop_back();
            }
            if (!cur.empty()) {
                used[cur.back()] = 0;
                res.push_back(cur.back());
                cur.pop_back();
            }
            ans.push_back(res);
            if (!cur.empty()) {
                dfs(u);
            } else {
                dfs(v);
            }
        } else {
            dfs(u);
            cur.push_back(v);
        }
    }

}



signed main() {
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    int n, m;
    cin >> n >> m;
    used.resize(n);
    g.resize(n);
    cing.resize(n);
    for (int i = 0; i < m; i++) {
        int v, u;
        cin >> v >> u;
        if (v > u)
            swap(u, v);
        cing[v - 1][u - 1]++;
    }
    for (int v = 0; v < n; v++) {
        for (auto [u, cn] : cing[v]) {
            while (cn > 1) {
                cn -= 2;
                ans.push_back({v, u});
            }
            if (cn == 1) {
                g[v].insert(u);
                g[u].insert(v);
                vert.insert({v, u});
                vert.insert({u, v});
            }
        }
    }
    dfs(0);
    for (auto s : ans) {
        for (auto el : s) {
            cout << el + 1 << ' ';
        }
        cout << '\n';
    }
}

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