Submission #1215305

#	Time	Username	Problem	Language	Result	Execution time	Memory
1215305		KindaGoodGames	Spring cleaning (CEOI20_cleaning)	C++17	0 / 100	1097 ms	7412 KiB

cleaning

#pragma GCC optimize("O3")
#include<bits/stdc++.h>

#define ll long long
#define pii pair<int,int>
#define tiii tuple<int,int,int>

using namespace std;

int n; 
vector<vector<int>> adj;
vector<int> par;
vector<bool> leaf;
vector<int> dp;
void DFS(int v, int p, vector<int>& dp, vector<int>& arr){
    dp[v] = arr[v];
    par[v] = p;
    if(adj[v].size() == 1 && arr[v] == 0){
        dp[v]++;
        leaf[v] = true;
    }

    for(auto u : adj[v]){
        if(u == p) continue;
        DFS(u,v,dp,arr);
        dp[v] += dp[u];
    }
}

int solve(int d, int r){
    map<int, int> oldDP;
    set<int> oldL;
    for(int i = 0; i < d; i++){
        int a;
        cin >> a;
        a--;
        if(leaf[a]){
            leaf[a] = false;
            oldL.insert(a);
            continue;
        }
        int node = a;
        while(par[node] != node){
            if(!oldDP.count(par[node])){
                oldDP[par[node]] = dp[par[node]];
            }
            dp[par[node]]++;
            node = par[node];
        }
        
        if(!oldDP.count(node)){
            oldDP[node] = dp[node];
        }
        dp[node]++;
    } 
 
    int cnt = 0;
    for(int i = 0; i < n; i++){
        if(dp[i] % 2 == 0){
            cnt++;
        }
    }

    int dpr = dp[r];

    // we remove the new leafs
    for(auto l : oldL){
        leaf[l] = true;
    }
    // reset dp values
    for(auto p : oldDP){
        dp[p.first] = p.second;
    }


    if(dpr % 2 == 1){ 
        return -1;
    } 
    return n + d + cnt - 2;
}

int main(){
    ios_base::sync_with_stdio(false);
    cin.tie(0);
    int q;
    cin >> n>> q;
    
    adj.resize(n);
    par.resize(n);

    for(int i = 0; i < n-1; i++){
        int a,b;
        cin >> a >> b;
        a--;b--;
        adj[a].push_back(b);
        adj[b].push_back(a);
    }

    int r = 0;
    for(int i = 0; i < n; i++){
        if(adj[i].size() > 1){
            r = i;
            break;
        }
    }

    dp.resize(n);
    vector<int> EMPTY(n);
    leaf.resize(n);
    DFS(r,r,dp,EMPTY);

    while(q--){
        int d;
        cin >> d;
        cout << solve(d, r) << "\n";
    }
}

• 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