Submission #939391

#	Time	Username	Problem	Language	Result	Execution time	Memory
939391		WonderfulWhale	Making Friends on Joitter is Fun (JOI20_joitter2)	C++17	1 / 100	5045 ms	17664 KiB

joitter2

#include<bits/stdc++.h>
using namespace std;

#define int int64_t
#define pb push_back
#define pii pair<int, int>
#define st first
#define nd second
#define sz(x) (int)(x).size()
#define all(x) (x).begin(), (x).end()

const int MAXN = 100'009;

int cnt[MAXN];
int p[MAXN];
int sz[MAXN];
set<int> in[MAXN];
set<int> out[MAXN];
int ans;

int Find(int x) {
	return x==p[x]?x:p[x]=Find(p[x]);
}

void Union(int a, int b) {
	a = Find(a);
	b = Find(b);
	//cout << "Union: " << a << " " << b << "\n";
	if(a==b) return;
	vector<int> union_queue;
	if(sz(out[a])+sz(in[a])<sz(out[b])+sz(in[b])) swap(a, b);
	for(int x:out[b]) {
		//cerr << "trying: "<< x << "\n";
		if(in[a].count(x)) {
			//cerr << "found: " << x << "\n";
			union_queue.pb(x);
		}
		//cerr << "adding: " << x << "\n";
		out[a].insert(x);
		in[x].erase(b);
		in[x].insert(a);
	}
	out[b].clear();
	//if(sz(in[a])<sz(in[b])) swap(a, b);
	for(int x:in[b]) {
		//cerr << "trying: "<< x << "\n";
		if(out[a].count(x)) {
			//cerr << "found: " << x << "\n";
			union_queue.pb(x);
		}
		in[a].insert(x);
		//cerr << "changin:  "<< x << " from: " << b << " to "<< a << "\n";
		out[x].erase(b);
		out[x].insert(a);
	}
	in[b].clear();
	p[b] = a;
	ans -= sz[a]*(sz[a]-1);
	ans -= sz[b]*(sz[b]-1);
	sz[a] += sz[b];
	ans += sz[a]*(sz[a]-1);
	for(int x:union_queue) {
		Union(a, x);
	}
}

set<pii> S;
set<int> used[MAXN];

int32_t main() {
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);

	int n, m;
	cin >> n >> m;
	iota(p, p+n+1, 0);
	fill(sz, sz+n+1, 1);
	for(int i=0;i<m;i++) {
		int a, b;
		cin >> a >> b;
		S.insert({a, b});
		int A = Find(a);
		int B = Find(b);
		if(A==B) goto skip;
		out[A].insert(B);
		in[B].insert(A);
		if(in[A].count(B)) {
			Union(A, B);
		}
		skip:
		int cnt = 0;
		for(int i=1;i<=n;i++) {
			used[i].clear();
		}
		for(pii x:S) {
			if(Find(x.st)==Find(x.nd)) continue;
			if(used[x.st].count(Find(x.nd))) continue;
			cnt += sz[Find(x.nd)];
			used[x.st].insert(Find(x.nd));
		}
		//cerr << ans << " " << cnt << "\n";
		cout << ans+cnt << "\n";
	}
}

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