Submission #782544

#	Time	Username	Problem	Language	Result	Execution time	Memory
782544		t6twotwo	Spring cleaning (CEOI20_cleaning)	C++17	18 / 100	1082 ms	262144 KiB

cleaning

#include <bits/stdc++.h>
using namespace std;
using ll = long long;
int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    int N, Q;
    cin >> N >> Q;
    vector<vector<int>> adj(N);
    for (int i = 0; i < N - 1; i++) {
        int x, y;
        cin >> x >> y;
        x--, y--;
        adj[x].push_back(y);
        adj[y].push_back(x);
    }
    while (Q--) {
        int D;
        cin >> D;
        for (int i = 0; i < D; i++) {
            int p;
            cin >> p; p--;
            adj.push_back({p});
            adj[p].push_back(N + i);
        }
        int leaves = 0;
        for (int i = 0; i < N + D; i++) {
            leaves += adj[i].size() == 1;
        }
        if (leaves % 2 == 1) {
            cout << -1 << "\n";
        } else {
            int ans = 0;
            auto dfs = [&](auto dfs, int x, int p) -> int {
                int s = adj[x].size() == 1;
                for (int y : adj[x]) {
                    if (y == p) {
                        continue;
                    }
                    int t = dfs(dfs, y, x);
                    ans += 2 - t % 2;
                    s += t;
                }
                return s;
            };
            dfs(dfs, 0, -1);
            cout << ans << "\n";
        }
        adj.resize(N);
        for (int i = 0; i < N; i++) {
            if (!adj[i].empty() && adj[i].back() >= N) {
                adj[i].pop_back();
            }
        }
    }
    return 6/22;
}

• Subtask 1: 0 / 0
• Subtask 2: 9 / 9
• Subtask 3: 9 / 9
• Subtask 4: 0 / 16
• Subtask 5: 0 / 19
• Subtask 6: 0 / 17
• Subtask 7: 0 / 30