Submission #578137

#	Time	Username	Problem	Language	Result	Execution time	Memory
578137		tengiz05	Spring cleaning (CEOI20_cleaning)	C++17	34 / 100	1095 ms	21336 KiB

cleaning

#include <bits/stdc++.h>

using namespace std;
using i64 = long long;

int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    
    int n, q;
    cin >> n >> q;
    
    vector<vector<int>> e(n);
    
    for (int i = 0; i < n - 1; i++) {
        int u, v;
        cin >> u >> v;
        u--;
        v--;
        e[u].push_back(v);
        e[v].push_back(u);
    }
    
    while (q--) {
        int k;
        cin >> k;
        
        vector<int> d(k);
        for (int i = 0; i < k; i++) {
            cin >> d[i];
            d[i]--;
        }
        
        auto adj = e;
        adj.resize(n + k);
        for (int i = 0; i < k; i++) {
            adj[d[i]].push_back(i + n);
        }
        
        int ans = 0;
        
        function<int(int, int)> dfs = [&](int u, int p) {
            int c = adj[u].size() <= 1;
            for (int v : adj[u]) {
                if (v != p) {
                    int s = dfs(v, u);
                    if (s % 2 == 0) {
                        ans += 2;
                    } else {
                        ans += 1;
                    }
                    c += s;
                }
            }
            return c;
        };
        
        int c = dfs(0, -1);
        
        if (c % 2 == 1) {
            cout << "-1\n";
        } else {
            cout << ans << "\n";
        }
    }
    
    return 0;
}

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