Submission #212118

#	Time	Username	Problem	Language	Result	Execution time	Memory
212118		abacaba	Making Friends on Joitter is Fun (JOI20_joitter2)	C++14	1 / 100	5060 ms	388616 KiB

joitter2

#include <iostream>
#include <string>
#include <unordered_map>
#include <unordered_set>
#include <cstring>
#include <chrono>
#include <vector>
#include <map>
#include <random>
#include <set>
#include <algorithm>
#include <math.h>
#include <cstdio>
#include <stdio.h>
#include <queue>
#include <bitset>
#include <cstdlib>
#include <deque>
#include <cassert>
#include <stack>
using namespace std;
 
#define mp make_pair
#define f first
#define se second
#define pb push_back
#define ppb pop_back
#define ll long long
#define ull unsigned long long
#define cntbit(x) __builtin_popcount(x)
#define endl '\n'
#define uset unordered_set
#define umap unordered_map
#define all(x) x.begin(), x.end()
#define pii pair<int, int>
#define ld long double
#define pll pair<long long, long long>
#define int long long

template <typename T> void Min(T &a, T b) {
    a = min(a, b);
}
 
template <typename T> void Max(T &a, T b) {
    a = max(a, b);
}
 
ostream &operator << (ostream &cout, vector <int> &a) {
	cout << "{";
	for (auto & it : a) cout << it << ", ";
	cout << "}";
	return cout;
}
 
ostream &operator << (ostream &cout, set <int> &a) {
	cout << "{";
	for (auto & it : a) cout << it << ", ";
	cout << "}";
	return cout;
}
 
const int mod = 1e9 + 7;
const int inf = 2e9;
const int N = 3e5 + 15;
int n, m, p[N], sz[N];
 
set <int> g[N], gr[N], gr_find[N];

queue <pii> q;

ll ans;

int find(int v) {
	if(v == p[v])
		return v;
	return p[v] = find(p[v]);
}

inline void upd_ans(int v, int sign) {
	ans += sign * (1ll * sz[v] * (sz[v] - 1) + 1ll * sz[v] * ((int)gr[v].size() - sz[v]));
}

inline void unio(int a, int b) {
	a = find(a);
	b = find(b);
	if(a != b) {
		upd_ans(a, -1);
		upd_ans(b, -1);

		// gr_find[b].erase(a);
		// gr_find[a].erase(b);

		// g[a].erase(b);
		// g[b].erase(a);

		for(int v : g[b]) {
			if(gr_find[a].count(v))
				q.push({v, a});

			gr_find[v].erase(b);
			gr_find[v].insert(a);
		}

		for(int v : gr_find[b]) {
			if(g[a].count(v))
				q.push({v, a});

			g[v].erase(b);
			g[v].insert(a);
		}

		gr[a].insert(gr[b].begin(), gr[b].end());
		gr_find[a].insert(gr_find[b].begin(), gr_find[b].end());
		g[a].insert(g[b].begin(), g[b].end());

		// gr_find[b].clear();
		// g[b].clear();
		// gr[b].clear();

		p[b] = a;
		sz[a] += sz[b];

		upd_ans(a, 1);
	}
}
 
main() {
	for(int i = 0; i < N; ++i)
		p[i] = i, sz[i] = 1, gr[i].insert(i);
	ios_base::sync_with_stdio(0); cout.tie(0); cin.tie(0);
	// freopen("input.txt", "r", stdin);
	cin >> n >> m;
	for(int i = 1; i <= m; ++i) {
		int u, v;
		cin >> u >> v;

		if(gr_find[find(u)].count(find(v))) {

 			q.push({find(u), find(v)});

 			while(!q.empty()) {
 				int u = q.front().f, v = q.front().se;
 				q.pop();
 				unio(u, v);
 			}
		}
		else {
			upd_ans(find(v), -1);

			gr_find[find(v)].insert(find(u));
			g[find(u)].insert(find(v));

			gr[find(v)].insert(u);

			upd_ans(find(v), 1);
		}
		cout << ans << endl;
	}
	return 0;
}

Compilation message (stderr)

joitter2.cpp:127:6: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
 main() {
      ^

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