Submission #431172

#	Time	Username	Problem	Language	Result	Execution time	Memory
431172		Kevin_Zhang_TW	Making Friends on Joitter is Fun (JOI20_joitter2)	C++17	17 / 100	5094 ms	224480 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];

ll cntin[MAX_N];
 
map<int, set<pair<int,int>>> in[MAX_N], 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]); }

void rm(int x, int u) {
	--cost[x], --cost[u];
	ans -= sz[ F(u) ];
	--cntin[ F(u) ];
	in[F(u)][F(x)].erase({x, u});
	out[F(x)][F(u)].erase({x, u});
}
void ad(int x, int u) {
	++cost[x], ++cost[u];
	ans += sz[ F(u) ];
	++cntin[ F(u) ];
	in[F(u)][F(x)].insert({x, u});
	out[F(x)][F(u)].insert({x, u});
}

bool mcnt(set<pair<int,int>> &st, int k) {
	return st.lower_bound({k, -1}) != st.upper_bound({k+1, -1});
}

void kick(int a, int b) {
	auto vec = out[F(a)][F(b)];
	for (auto [x, y] : vec) rm(x, y);
}

bool no_merge(int a, int b) {
	if (F(a) == F(b)) return true;
	if (out[F(b)][F(a)].empty()) return true;
	return false;
}
void add_edge(int a, int b) {
	if (F(a) == F(b)) return;
	// if a already connected to group(b), then nothing happen
	if (mcnt(in[F(b)][F(a)], a)) return;
	ad(a, b);
	if (out[F(b)][F(a)].empty()) return;

	a = F(a), b = F(b);

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

	vector<pair<int,int>> kl;
	for (auto [_, vec] : in[a])
		for (auto p : vec) kl.pb(p);
		//kl.insert(end(kl), AI(vec));
	for (auto [_, vec] : out[a]) 
		for (auto p : vec) kl.pb(p);
		//kl.insert(end(kl), AI(vec));

	in[a].clear(), out[a].clear();

	for (auto [x, y] : kl) rm(x, y);

	ans += 2ll * sz[a] * sz[b] + 1ll * cntin[b] * sz[a];

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

	vector<pair<int,int>> tmp;
	for (auto [x, y] : kl) {
		if (no_merge(x, y))
			add_edge(x, y);
		else tmp.pb(x, y);
	}
	for (auto [x, y] : tmp)
		add_edge(x, y);
}
 
int32_t main() {
	ios_base::sync_with_stdio(0), cin.tie(0);
	cin >> n >> m;
	vector<pair<int,int>> alle(m);
	for (auto &[a, b] : alle) cin >> a >> b;
	vector<ll> res;

	init();
	for (auto [a, b] : alle) {
		add_edge(a, b);
		res.pb(ans);
	}
	for (auto i : res) cout << i << '\n';

}

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