Submission #430970

#	Time	Username	Problem	Language	Result	Execution time	Memory
430970		Kevin_Zhang_TW	Making Friends on Joitter is Fun (JOI20_joitter2)	C++17	0 / 100	6 ms	9676 KiB

joitter2

#include <bits/stdc++.h>
using namespace std;
using ll = long long;
#define pb emplace_back
#define AI(i) begin(i), end(i)
template<class T> bool chmin(T &a, T b) { return b < a && (a = b, true); }
template<class T> bool chmax(T &a, T b) { return a < b && (a = b, true); }
#ifdef KEV
#define DE(args...) kout("[ " + string(#args) + " ] = ", args)
void kout() { cerr << endl; }
template<class T, class ...U> void kout(T a, U ...b) { cerr << a << ' ', kout(b...); }
template<class T> void debug(T l, T r) { while (l != r) cerr << *l << " \n"[next(l)==r], ++l; }
#else
#define DE(...) 0
#define debug(...) 0
#endif
// My bug list :
// integer overflow
// 0based, 1based forgotten
// index out of bound
// n, m, i, j typo
// some cases are missing
 
const int MAX_N = 100010;
 
ll ans;
 
int n, m, g[MAX_N], sz[MAX_N];
 
//unordered_set<int> in[MAX_N], out[MAX_N];
set< pair<int,int> > in[MAX_N], out[MAX_N];

//set<int> out[MAX_N];
 
void init() {
	iota(g, g+n+1, 0);
	fill(sz, sz + n + 1, 1);
}
 
int F(int i) { return i == g[i] ? i : g[i] = F(g[i]); }

pair<int,int> tok(int i) {
	return make_pair(F(i), i);
}
 
 
void kill_edge(int a, int b) {
	in[F(b)].erase(tok(a));
	out[F(a)].erase(tok(b));
}
void clean(int a, int b) {
	vector<int> ina;//(AI(in[a]));
	for (auto [g, id] : in[a]) ina.pb(id);
	for (int x : ina) {
		if (F(x) == b) {
			kill_edge(x, a);
//			in[a].erase(tok(x));
//			out[F(x)].erase(a);
			ans -= sz[ a ];
		}
	}
}

void resetg(set<pair<int,int>> &st, int a, int b) {
	auto it = st.lower_bound(make_pair(a, -1));
	vector<pair<int,int>> pt;
	while (it != end(st) && it->first == a) {
		pt.pb(*it);
		it = st.erase(it);
	}
	for (auto [x, y] : pt)
		st.insert({b, y});
}
void add_edge(int a, int b) {
	if (F(a) == F(b)) return;
	if (in[ F(b) ].count(tok(a))) return;
	ans += sz[ F(b) ];
	in[F(b)].insert(tok(a));
	out[F(a)].insert(tok(b));

	//if (out[F(b)].count(F(a))) {
	auto it = out[F(b)].lower_bound(make_pair(F(a), -1));

	if (it != end(out[F(b)]) && it->first == F(a)) {
		a = F(a), b = F(b);
		clean(a, b), clean(b, a);
 
		ans -= 1ll * sz[a] * in[a].size() + 1ll * sz[b] * in[b].size();
		ans += 2ll * sz[a] * sz[b];

		vector<pair<int,int>> kl;
		for (auto [g, id] : in[a]) kl.pb(id, a);
		for (auto [g, id] : in[b]) kl.pb(id, b);
		//vector<int> nin(AI(in[a])); nin.insert(end(nin), AI(in[b]));
 
		for (auto [g, id] : out[a]) {
			resetg(in[id], a, b);
		}

		for (auto [a, b] : kl) kill_edge(a, b);

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

		out[b].insert(AI(out[a]));
		out[a].clear();
 
		for (auto [a, b] : kl) add_edge(a, b);
		//for (int i : nin) add_edge(i, a);
	}
}
int32_t main() {
	ios_base::sync_with_stdio(0), cin.tie(0);
	cin >> n >> m;
	init();
	while (m--) {
		int a, b;
		cin >> a >> b;
		add_edge(a, b);
		cout << ans << '\n';
   	}
}

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