Submission #1218214

#	Time	Username	Problem	Language	Result	Execution time	Memory
1218214		__moin__	Spring cleaning (CEOI20_cleaning)	C++20	0 / 100	191 ms	9424 KiB

cleaning

#include <bits/stdc++.h>
using namespace std;

// #define int long long
const int INF = 1e9;

int clamp(int x) {
    return min(x, INF);
}

        vector<int> dp(2e5);
        vector<bool> par(2e5);
        vector<int> parent(2e5);
        vector<int> par_pref(2e5);
        vector<int> neg_par_pref(2e5);

__int32_t main() {
    // ios::sync_with_stdio(0); cin.tie(0);

    int n,q; cin >> n >> q;
    vector<vector<int>> adj(n);
    for (int i = 1; i < n; i++) {
        int a, b; cin >> a >> b; a--; b--;
        adj[a].push_back(b);
        adj[b].push_back(a);
    }
    function<void(int,int)> dfs = [&](int v, int p) {
        parent[v] = p;
        bool thispar = adj[v].size() == 1;
        int sum = 0;
        for (int nn : adj[v]) {
            if (nn != p) {
                dfs(nn, v);
                thispar ^= par[nn];
                sum += dp[nn];
            }
        }
        par[v] = thispar;
        dp[v] = sum + (2 - par[v]);
    };
    dfs(0, -1);
    function<void(int,int,int,int)> dfs_par = [&](int v, int p, int pref, int neg_pref) {
        par_pref[v] = pref + par[v];
        neg_par_pref[v] = neg_pref + 1 - par[v];
        for (int nn : adj[v]) {
            if (nn != p) {
                dfs_par(nn, v, par_pref[v], neg_par_pref[v]);
            }
        }
    };
    dfs_par(0, -1, 0, 0);

    // ONE QUERY ONLY
    for (int Q = 0; Q < q; Q++) {
        // auto adj_local = adj;
        int m; cin >> m;
        // vector<int> revert(m);
        // vector<bool> marked(n+m);
        // for (int i = 0; i < m; i++) {
            int x; cin >> x; x--;

                if (par[0] + (adj[x].size() != 1)) cout << -1 << "\n";
        else {
            // if (adj[x].size() != 1)
            // cout << (dp[0] - 2 + par[0]) - neg_par_pref[x] + par_pref[x] << "\n";
            cout << (dp[0] - 2 + par[0]) + 1 << "\n";
        }

        //     revert[i] = x;
        //     adj.push_back({x});
        //     adj[x].push_back(n++);
        //     marked[n-1] = 1;
        //     while (x != -1) {
        //         marked[x] = 1;
        //         x = parent[x];
        //     }
        // }
        // function<void(int,int)> dfs2 = [&](int v, int p) {
        //     if (!marked[v]) return;
        //     bool thispar = adj[v].size() == 1;
        //     int sum = 0;
        //     for (int nn : adj[v]) {
        //         if (nn != p) {
        //             dfs2(nn, v);
        //             thispar ^= par[nn];
        //             sum += dp[nn];
        //         }
        //     }
        //     par[v] = thispar;
        //     dp[v] = sum + (2 - par[v]);
        // };
        // dfs2(0, -1);
        // if (par[0]) cout << -1 << "\n";
        // else cout << dp[0] - 2 + par[0] << "\n";
        // n -= m;
        // adj.resize(n);
        // for (int e : revert) adj[e].pop_back();
        // dfs2(0, -1);
    }


    return 0;
}

• 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