Submission #888424

#	Time	Username	Problem	Language	Result	Execution time	Memory
888424		8pete8	Spring cleaning (CEOI20_cleaning)	C++17	28 / 100	1072 ms	12708 KiB

cleaning

#include<iostream>
#include<stack>
#include<map>
#include<vector>
#include<string>
#include<unordered_map>
#include <queue>
#include<cstring>
#include <cassert>
#include<limits.h>
#include<cmath>
#include<set>
#include<algorithm>
#include<bitset>
#include <iomanip>  
#include <cstdio>
#include <cstdlib>
#include <cstring>
using namespace std;
#define ll long long    
#define f first
#define endl "\n"
#define s second
#define pii pair<int,int>
#define ppii pair<int,pii>
#define vi vector<int>
#define pb push_back
//#define p push
#define all(x) x.begin(),x.end()
#define rall(x) x.rbegin(),x.rend()
#define F(n) for(int i=0;i<n;i++)
#define lb lower_bound
#define ub upper_bound
#define fastio ios::sync_with_stdio(false);cin.tie(NULL);
using namespace std;
#pragma GCC optimize ("03,unroll-loops")
#define int long long
const int mxn=1e5+5,inf=1e9,lg=30,mod=1e9+7;
int n,q;
vector<int>adj[mxn+10];
int val[mxn+10],ans=0,up[mxn+10],cnt=0;
bool leaf[mxn+10],yes[mxn+10];
int st=1;
void dfs(int cur,int p){
  for(auto i:adj[cur]){
    if(i==p)continue;
    dfs(i,cur);
    up[i]=cur;
    val[cur]+=val[i];
  }
  if(val[cur]==0||val[cur]%2)val[cur]=1;
  else val[cur]=2;
  if(cur!=st)ans+=val[cur];
}
int32_t main(){
    fastio
    cin>>n>>q;
    for(int i=0;i<n-1;i++){
      int a,b;cin>>a>>b;
      adj[a].pb(b);
      adj[b].pb(a);
    }
    
    for(int i=1;i<=n;i++)if(adj[i].size()==2)st=i;
    for(int i=1;i<=n;i++){
      if(adj[i].size()==1){
        leaf[i]=true;
        if(i!=st)val[i]++;
        cnt++;
      }
    }
    dfs(st,-1);
    while(q--){// brute force,check idea
      int m;cin>>m;
      vector<int>v(m);
      for(int i=0;i<m;i++){
        cin>>v[i];
        int a=v[i];
        if(!leaf[a]||yes[a]){
          cnt++;
          while(a!=st){
            if(val[a]==1)val[a]=2,ans++;
            else val[a]=1,ans--;
            a=up[a];
          }
        }
        else yes[a]=true;
      }
      for(auto i:v)yes[i]=false;
      cout<<((cnt%2)?-1:ans+m)<<'\n';
      for(auto i:v){
        int a=i;
        if(!leaf[a]||yes[a]){
          cnt--;
          while(a!=st){
            if(val[a]==1)val[a]=2,ans++;
            else val[a]=1,ans--;
            a=up[a];
          }
        }
        else yes[a]=true;
      }
      for(auto i:v)yes[i]=false;
    }
    return 0;
}

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