Submission #431088

#	Time	Username	Problem	Language	Result	Execution time	Memory
431088		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], cost[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(F(b));
}
 
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 kick(int a, int b) {
	auto it = in[a].lower_bound(make_pair(b, -1));
	vector<pair<int,int>> pt;
	while (it != end(in[a]) && it->first == b)
		pt.pb(*it++);
	for (auto [_, y] : pt) {
		kill_edge(y, a);
		ans -= sz[a];
	}
}
 
bool hg(set<pair<int,int>> &st, int v) {
	return st.lower_bound({v, -1}) != st.lower_bound({v+1, -1});
}
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(F(b));

	++cost[F(a)], ++cost[F(b)];
 
	if (out[F(b)].count(F(a))) {
		a = F(a), b = F(b);
 
		kick(a, b), kick(b, a);

		if (cost[a] > cost[b]) swap(cost[a], cost[b]);

		vector<int> nmg;

		for (int x : out[a]) {
			if (hg(in[b], x)) {
				nmg.pb(x);
			}
			else {
				resetg(in[x], a, b);
				out[b].insert(x);
			}
		}

		ans += in[b].size() * 1ll * sz[a];

		for (auto [g, id] : in[a]) {
			if (out[b].count(g)) {
				nmg.pb(g);
			}
			else {
				out[g].erase(a), out[g].insert(b);
				in[b].insert({g, id});
				ans += sz[b];
			}
		}
// 
		for (int x : nmg) {
			kick(a, x), kick(x, a), kick(x, b), kick(b, x);
		}

		ans += 2ll * sz[a] * sz[b];
 
		g[a] = b;
		cost[b] += cost[a];
		sz[b] += sz[a];

		for (int x : nmg) add_edge(x, a), add_edge(a, x);
	}
}
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