Submission #987102

#	Time	Username	Problem	Language	Result	Execution time	Memory
987102		aykhn	Spring cleaning (CEOI20_cleaning)	C++17	34 / 100	1051 ms	22612 KiB

cleaning

#include <bits/stdc++.h>

using namespace std;

#define int long long
#define inf 0x3F3F3F3F3F3F3F3F

const int MXN = 2e5 + 5;

int n, q, r;
vector<int> adj[MXN];
int cnt[MXN], add[MXN], leaf, res;

void dfs(int a, int p)
{
    cnt[a] = 0;
    int f = 1;
    for (int v : adj[a])
    {
        if (v == p) continue;
        f = 0;
        dfs(v, a);
        cnt[a] += cnt[v];
        if (cnt[v] & 1) res++;
        else res += 2;
    }
    leaf += f;
    cnt[a] += f;
}

signed main() 
{
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cin >> n >> q;
    for (int i = 1; i < n; i++)
    {
        int u, v;
        cin >> u >> v;
        adj[u].push_back(v);
        adj[v].push_back(u);
    }
    for (int i = 1; i <= n; i++) 
    {
        if (adj[i].size() >= 2) 
        {
            r = i;
            break;
        }
    }
    for (int i = 1; i <= q; i++)
    {
        set<int> s;
        int d;
        cin >> d;
        for (int j = 1; j <= d; j++)
        {
            int x;
            cin >> x;
            add[x]++;
            s.insert(x);
        }
        int m = n;
        for (int j = 1; j <= m; j++)
        {
            for (int k = 1; k <= add[j]; k++) 
            {
                adj[j].push_back(++n);
            }
        }
        res = leaf = 0;
        dfs(r, r);
        if (leaf & 1) cout << -1 << '\n';
        else cout << res << '\n';
        for (int j = 1; j <= m; j++)
        {
            for (int k = 1; k <= add[j]; k++) 
            {
                adj[j].pop_back(), n--;
            }
            add[j] = 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