Submission #866278

#	Time	Username	Problem	Language	Result	Execution time	Memory
866278		epicci23	Logičari (COCI21_logicari)	C++17	10 / 110	173 ms	30164 KiB

Main

#include "bits/stdc++.h"
using namespace std;
#define int long long
#define endl '\n'
#define all(x) (x).begin(),(x).end()
#define pb push_back
#define sz(x) ((int)(x).size())


constexpr int N = 1e5 + 5;
constexpr int INF = 1e9;

int dp[N][2][2][2][2];
vector<int> v[N];
int par[N];
int u,w;

int find(int a){
  if(par[a]==a) return a;
  return par[a]=find(par[a]);
}

bool unite(int a,int b){
  a=find(a),b=find(b);
  if(a==b) return 0;
  par[a]=b;
  return 1;
}

int dfs(int c,int p,int fl1,int fl2,int rt,int sp){

  if(c==u && fl1!=rt) return INF;
  if(c==w && fl1!=sp) return INF;
  if(c==w && fl2 && rt) return INF;
  if(dp[c][fl1][fl2][rt][sp]!=-1) return dp[c][fl1][fl2][rt][sp];

  int hm = fl2 + (c==u && sp);

  for(int x:v[c]){
    if(x==p) continue;
    if(x==w) hm+=sp;
  }

  if(hm>=2) return INF;
  
  int cur = 0;
   
  for(int x:v[c]){
    if(x==p) continue;
    cur+=dfs(x,c,0,fl1,rt,sp);
  }

  if(hm==1){
    return dp[c][fl1][fl2][rt][sp]=cur+fl1;
  }
  else{
    int lol = INF;
    for(int x:v[c]){
      if(x==p) continue;
      int xd = cur - dfs(x,c,0,fl1,rt,sp);
      xd+=dfs(x,c,1,fl1,rt,sp);
      lol=min(lol,xd);
    }
    return dp[c][fl1][fl2][rt][sp]=lol+fl1;
  }
}


void solve(){

  int n;
  cin >> n;
  
  memset(dp,-1,sizeof(dp));

  iota(par,par+N,0LL);

  

  for(int i=1;i<=n;i++){
    int a,b;
    cin >> a >> b;

    if(!unite(a,b)){
      u=a;
      w=b;
    }
    else{
     v[a].pb(b);
     v[b].pb(a);
    }
  }
  

  for(int i=0;i<sz(v[u]);i++){
    if(v[u][i]==w) v[u].erase(v[u].begin()+i);
  } 

  for(int i=0;i<sz(v[w]);i++){
    if(v[w][i]==u) v[w].erase(v[w].begin()+i);
  } 

  int ans = INF;
  
  ans=min(ans,dfs(u,u,1,0,1,0));
  ans=min(ans,dfs(u,u,1,0,1,1));
  ans=min(ans,dfs(u,u,0,0,0,0));
  ans=min(ans,dfs(u,u,0,0,0,1));

  if(ans>n) cout << -1 << endl;
  else cout << ans << endl;
}


int32_t main(){

  ios::sync_with_stdio(0);
  cin.tie(0);

  int t=1;//cin >> t;
  while(t--) solve();
}

• Subtask 1: 10 / 10
• Subtask 2: 0 / 10
• Subtask 3: 0 / 40
• Subtask 4: 0 / 50