Submission #1279101

#	Time	Username	Problem	Language	Result	Execution time	Memory
1279101		PlayVoltz	Making Friends on Joitter is Fun (JOI20_joitter2)	C++20	100 / 100	761 ms	66340 KiB

joitter2

#include <cstdio>
#include <stdio.h>
#include <stdbool.h>
#include <iostream>
#include <map>
#include <vector>
#include <climits>
#include <stack>
#include <string>
#include <queue>
#include <algorithm>
#include <set>
#include <unordered_set>
#include <unordered_map>
#include <cmath>
#include <cctype>
#include <bitset>
#include <iomanip>
#include <cstring>
#include <numeric>
#include <cassert>
#include <random>
using namespace std;
 
#define int long long
#define pii pair<int, int>
#define mp make_pair
#define pb push_back
#define fi first
#define se second

int ans=0;
queue<pii> ord;
vector<int> dsu, sz;
vector<set<int> > graph, tgraph, child;

int fp(int a){
	if (dsu[a]==-1)return a;
	return dsu[a]=fp(dsu[a]);
}

void insert(int a, int b){
	graph[a].insert(b);
	tgraph[b].insert(a);
	if (graph[b].find(a)!=graph[b].end())ord.push(mp(a, b));
}

void merge(int a, int b){
	a=fp(a), b=fp(b);
	if (a==b)return;
	if (sz[a]+graph[a].size()+child[a].size()>sz[b]+graph[b].size()+child[b].size())swap(a, b);
	ans+=sz[a]*child[b].size()+sz[b]*child[a].size();
	sz[b]+=sz[a];
	dsu[a]=b;
	for (auto c:child[a]){
		if (child[b].find(c)==child[b].end())child[b].insert(c);
		else ans-=sz[b];
	}
	graph[a].erase(b);
	tgraph[b].erase(a);
	graph[b].erase(a);
	tgraph[a].erase(b);
	for (auto c:graph[a])tgraph[c].erase(a), insert(b, c);
	for (auto c:tgraph[a])graph[c].erase(a), insert(c, b);
}

int32_t main(){
	ios_base::sync_with_stdio(0);
	cin.tie(0);
	cout.tie(0);
	int n, q, a, b;
	cin>>n>>q;
	graph.resize(n+1);
	tgraph.resize(n+1);
	dsu.resize(n+1, -1);
	sz.resize(n+1, 1);
	child.resize(n+1);
	for (int i=1; i<=n; ++i)child[i].insert(i);
	while (q--){
		cin>>a>>b;
		b=fp(b);
		if (fp(a)!=b&&child[b].find(a)==child[b].end()){
			child[b].insert(a);
			ans+=sz[b];
			a=fp(a);
			insert(a, b);
			while (ord.size())merge(ord.front().fi, ord.front().se), ord.pop();
		}
		cout<<ans<<"\n";
	}
}

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