Submission #212105

#	Time	Username	Problem	Language	Result	Execution time	Memory
212105		kshitij_sodani	Making Friends on Joitter is Fun (JOI20_joitter2)	C++17	100 / 100	651 ms	53508 KiB

joitter2

#include <iostream>
#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
#define mp make_pair
#define pb push_back
#define a first
#define b second
#define endl "\n"
ll par[100001];
ll size2[100001];
set<pair<ll,ll>> inc[100001];
set<pair<ll,ll>> out[100001];
ll find(ll no){
	if(par[no]==no){
		return no;
	}
	par[no]=find(par[no]);
	return par[no];
}
set<ll> wait;
ll ans=0;
ll count(ll aa){
	return (ll)size2[aa]*(size2[aa]-1)+(ll)inc[aa].size()*size2[aa];
}
void merge(ll aa,ll bb){
	ans-=(count(aa)+count(bb));
	if((inc[aa].size()+out[aa].size())<(inc[bb].size()+out[bb].size())){
		swap(aa,bb);
	}

	for(auto no:inc[bb]){
		if(no.a==aa){
			auto it=out[aa].find({bb,no.b});
			out[aa].erase(it);
			continue;
		}
		auto it=inc[no.a].lower_bound({aa,0});
		if(it!=inc[no.a].end() and it->a==aa){
			wait.insert(no.a);
		}
		out[no.a].insert({aa,no.b});
		auto tt=out[no.a].find({bb,no.b});
		out[no.a].erase(tt);
		inc[aa].insert(no);
	}
	for(auto no:out[bb]){
		if(no.a==aa){
			auto it=inc[aa].find({bb,no.b});
			inc[aa].erase(it);
			continue;
		}
		auto it=out[no.a].lower_bound({aa,0});
		if(it!=out[no.a].end() and it->a==aa){
			wait.insert(no.a);
		}
		inc[no.a].insert({aa,no.b});
		auto tt=inc[no.a].find({bb,no.b});
		inc[no.a].erase(tt);
		out[aa].insert(no);
	}
	inc[bb].clear();
	out[bb].clear();
	par[bb]=aa;
	size2[aa]+=size2[bb];
	ans+=count(aa);
	//cout<<":: "<<ans<<" "<<aa<<" "<<bb<<" "<<inc[aa].size()<<endl;
	if(wait.size()>0){
		ll xx=*(wait.begin());
		wait.erase(wait.begin());
		merge(aa,xx);
	}


}
int main(){
	ios_base::sync_with_stdio(false);
	cin.tie(NULL);
	ll tot=0;
	ll n,m;
	cin>>n>>m;
	for(ll i=0;i<n;i++){
		par[i]=i;
		size2[i]=1;
	}
	ll aa,bb;
	for(ll i=0;i<m;i++){
		cin>>aa>>bb;
		aa-=1;
		bb-=1;
		ll ac=aa;
		aa=find(aa);
		bb=find(bb);
		if(aa==bb){
			cout<<ans<<endl;
			continue;
		}
		if(out[aa].find({bb,ac})==out[aa].end()){
			auto it=inc[aa].lower_bound({bb,0});
			if(it!=inc[aa].end() and it->a==bb){
				merge(aa,bb);
			}
			else{
				inc[bb].insert({aa,ac});
				out[aa].insert({bb,ac});
				ans+=size2[bb];
			}
		}
		cout<<ans<<endl;
	}


	return 0;
}

Compilation message (stderr)

joitter2.cpp: In function 'int main()':
joitter2.cpp:79:5: warning: unused variable 'tot' [-Wunused-variable]
  ll tot=0;
     ^~~

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