Submission #1096033

#	Time	Username	Problem	Language	Result	Execution time	Memory
1096033		_8_8_	Spring cleaning (CEOI20_cleaning)	C++17	34 / 100	1071 ms	17752 KiB

cleaning

#include <bits/stdc++.h>
    
using namespace std;
    
typedef long long ll;
const int  N = 2e5 + 12, MOD = (int)1e9 + 7;
 
int n, q, rt;
ll cur = 0;
int dp[N], s[N];
vector<int> g[N];
void dfs(int v, int pr = -1) {
    s[v] = 0;
    bool is = 1;
    for(int to:g[v]) {
        if(to == pr) continue;
        is = 0;
        dfs(to, v);
        s[v] += s[to];
        cur += (s[to] & 1 ? 1 : 2);
    }
    s[v] += (is);
}
void test() {
    cin >> n >> q;
    for(int i = 1; i <= n - 1; i++) {
        int a, b;
        cin >> a >> b;
        g[a].push_back(b);
        g[b].push_back(a);
    }
 
    for(int i = 1; i <= n; i++) {
        if((int)g[i].size() != 1) {
            rt = i;
            break;
        }
    }
    while(q--) {
        cur =0 ;
        int d;
        cin >> d;
        vector<int> a(d);
        for(int j = 0; j < d; j++) {       
            cin >> a[j];
            g[a[j]].push_back(n + j + 1);
        }
        dfs(rt);
        if(s[rt] & 1) {
            cur = -1;
        }
        cout << cur << '\n';
        for(int i = 0; i < d; ++i) {
            g[a[i]].pop_back();
        }
    }
}
int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(0); 
 
    int t = 1; 
    // cin >> t;
    
    while(t--) 
        test();
    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