Submission #784311

#	Time	Username	Problem	Language	Result	Execution time	Memory
784311		t6twotwo	Spring cleaning (CEOI20_cleaning)	C++17	0 / 100	1064 ms	12884 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);
    }
    vector<int> v(N), par(N, -1);
    auto dfs = [&](auto dfs, int x) -> void {
        if (adj[x].size() == 1) {
            v[x] = 1;
        }
        for (int y : adj[x]) {
            if (y == par[x]) {
                continue;
            }
            par[y] = x;
            dfs(dfs, y);
            v[x] ^= v[y];
        }
    };
    dfs(dfs, 0);
    int ans = 2 * (N - 1) - count(v.begin(), v.end(), 1);
    vector<int> deg(N);
    for (int i = 0; i < N; i++) {
        deg[i] = adj[i].size();
    }
    while (Q--) {
        int D;
        cin >> D;
        vector<int> a(D);
        for (int &p : a) {
            cin >> p; p--;
            if (deg[p] != 1) {
                ans += v[p] == 0 ? -1 : 1;
                v[p] ^= 1;
            }
            deg[p]++;
            int x = par[p];
            while (x != -1) {
                ans += v[x] == 0 ? -1 : 1;
                v[x] ^= 1;
                x = par[x];
            }
        }
        if (v[0] == 1) {
            cout << -1 << "\n";
        } else {
            cout << ans + D << "\n";
        }
        for (int p : a) {
            deg[p]--;
            if (deg[p] != 1) {
                ans += v[p] == 0 ? -1 : 1;
                v[p] ^= 1;
            }
            int x = par[p];
            while (x != -1) {
                ans += v[x] == 0 ? -1 : 1;
                v[x] ^= 1;
                x = par[x];
            }
        }
    }
    return 6/22;
}

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