Submission #966383

#	Time	Username	Problem	Language	Result	Execution time	Memory
966383		anton	Spring cleaning (CEOI20_cleaning)	C++17	9 / 100	1033 ms	11328 KiB

cleaning

#include<bits/stdc++.h>

using namespace std;
#define int long long
#define pii pair<int, int>
typedef complex<int> point;
const int MAX_N = 100000;

vector<vector<int>> adj;
vector<int> parity;
vector<int> anc;
vector<int> cost = {2, 1};
int total_cost= 0;

int count_leaves(int u, int a){
    int s= 0;
    for(auto v: adj[u]){
        if(v!=a){
            anc[v] = u;
            s+=count_leaves(v, u);
        }
    }
    if(s==0){
        s=1;
    }
    total_cost+= cost[s%2];
    
    //cout<<u+1<<" "<<s<<endl;
    parity[u] = s%2;
    return s%2;
}

void flip(int u){
    //cout<<"flip "<<u+1<<endl;
    total_cost -= cost[parity[u]];
    parity[u] ^= 1;
    total_cost+=cost[parity[u]];
    if(anc[u]!=-1){
        flip(anc[u]);
    }
}
signed main(){
    cin.tie(NULL);
    ios_base::sync_with_stdio(false);
    int n, k;
    cin>>n>>k;
    adj.resize(n);
    parity.resize(n);
    anc.resize(n, -1);
    int node = 0;
    int deg=  0;

    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);
        if(adj[a].size()>deg){
            node =a;
            deg = adj[a].size();
        }
        if(adj[b].size()>deg){
            node =b;
            deg = adj[b].size();
        }
    }

    
    int r=count_leaves(node, -1);

    //cout<<"base "<<total_cost<<endl;
    for(int i = 0; i<k; i++){
        int d;
        cin>>d;
        vector<int> parents;
        for(int j = 0; j<d; j++){
            int v;
            cin>>v;
            v--;
            parents.push_back(v);
            adj[parents.back()].push_back(adj.size());
            total_cost++;
            if(adj[parents.back()].size()>2){
                flip(parents.back());
                r^=1;
            }
        }
        if(r%2==1){
            cout<<-1<<endl;
        }
        else{
            cout<<total_cost-2<<endl;
        }
        
        adj.resize(n);
        for(auto e: parents){
            if(adj[e].size()>2){
                flip(e);
                r^=1;
            }
            total_cost--;
            adj[e].pop_back();
        }
    }
}

Compilation message (stderr)

cleaning.cpp: In function 'int main()':
cleaning.cpp:59:25: warning: comparison of integer expressions of different signedness: 'std::vector<long long int>::size_type' {aka 'long unsigned int'} and 'long long int' [-Wsign-compare]
   59 |         if(adj[a].size()>deg){
      |            ~~~~~~~~~~~~~^~~~
cleaning.cpp:63:25: warning: comparison of integer expressions of different signedness: 'std::vector<long long int>::size_type' {aka 'long unsigned int'} and 'long long int' [-Wsign-compare]
   63 |         if(adj[b].size()>deg){
      |            ~~~~~~~~~~~~~^~~~

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