Submission #706781

#	Time	Username	Problem	Language	Result	Execution time	Memory
706781		EthanKim8683	Making Friends on Joitter is Fun (JOI20_joitter2)	C++17	0 / 100	7 ms	14408 KiB

joitter2

#include<bits/stdc++.h>
using namespace std;
using I=int;
using Lli=long long int;
using B=bool;
const I N=100000;
set<pair<I,I>>viss;
I pars[N];
set<I>incs[N],outs[N],nods[N];
Lli res=0;
I fnd(I i){
  return pars[i]<0?i:pars[i]=fnd(pars[i]);
}
I siz(I i){
  return-pars[fnd(i)];
}
B con(I a,I b){
  return fnd(a)==fnd(b);
}
void uni(I a,I b){
  if((a=fnd(a))==(b=fnd(b)))return;
  if(pars[a]>pars[b])swap(a,b);
  Lli siz1=siz(a),siz2=siz(b);
  res-=siz1*(incs[a].size()+siz1-1);
  res-=siz2*(incs[b].size()+siz2-1);
  for(auto c:incs[b]){
    outs[c].erase(b);
    if(fnd(c)!=a){
      incs[a].insert(c);
      outs[c].insert(a);
    }
  }
  for(auto c:nods[b]){
    nods[a].insert(c);
    if(outs[c].count(a)){
      outs[c].erase(a);
      incs[a].erase(c);
    }
  }
  pars[a]+=pars[b],pars[b]=a;
  Lli siz3=siz(a);
  res+=siz3*(incs[a].size()+siz3-1);
}
I main(){
  cin.tie(0)->sync_with_stdio(0);
  I n,m;cin>>n>>m;
  fill_n(pars,n,-1);
  for(I i=0;i<n;i++)nods[i].insert(i);
  for(I i=0;i<m;i++){
    I a,b;cin>>a>>b,a--,b--;
    if(!con(a,b)&&!outs[a].count(fnd(b))){
      incs[fnd(b)].insert(a);
      outs[a].insert(fnd(b));
      res+=siz(b);
    }
    viss.insert({a,b});
    if(viss.count({b,a}))uni(a,b);
    printf("%lli\n",res);
  }
}

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