Submission #692105

#	Time	Username	Problem	Language	Result	Execution time	Memory
692105		EthanKim8683	Making Friends on Joitter is Fun (JOI20_joitter2)	C++17	0 / 100	6 ms	9684 KiB

joitter2

#include<bits/stdc++.h>
using namespace std;
using I=int;
using Lli=long long int;
const I N=100000;
const I M=300000;
pair<I,I>fols[M];
set<pair<I,I>>viss;
set<I>incs[N],outs[N];
I pars[N];
Lli res=0;
I fnd(I i){
  if(pars[i]<0)return i;
  return pars[i]=fnd(pars[i]);
}
void uni(I a,I b){
  if((a=fnd(a))==(b=fnd(b)))return;
  if(pars[a]>pars[b])swap(a,b);
  res-=(Lli)-pars[a]*(-pars[a]-1);
  res-=(Lli)-pars[b]*(-pars[b]-1);
  res-=(Lli)-pars[a]*incs[a].size();
  res-=(Lli)-pars[b]*incs[b].size();
  for(auto c:incs[b]){
    outs[c].erase(b);
    if(a!=c){
      outs[c].insert(a);
      incs[a].insert(c);
    }
  }
  for(auto c:outs[b]){
    incs[c].erase(b);
    if(a!=c){
      incs[c].insert(a);
      outs[a].insert(c);
    }
  }
  pars[a]+=pars[b],pars[b]=a;
  res+=(Lli)-pars[a]*(-pars[a]-1);
  res+=(Lli)-pars[a]*incs[a].size();
}
I main(){
  cin.tie(0)->sync_with_stdio(0);
  I n,m;cin>>n>>m;
  for(I i=0;i<m;i++){
    I a,b;cin>>a>>b,a--,b--;
    fols[i]={a,b};
  }
  fill_n(pars,n,-1);
  for(I i=0;i<m;i++){
    auto[a,b]=fols[i];
    if(viss.count({b,a})){
      uni(a,b);
    }else{
      viss.insert({a,b});
      a=fnd(a),b=fnd(b);
      if(!outs[a].count(b)){
        outs[a].insert(b);
        incs[b].insert(a);
        res+=-pars[b];
      }
    }
    printf("%lli\n",res);
  }
}

• Subtask 1: 0 / 1
• Subtask 2: 0 / 16
• Subtask 3: 0 / 83