Submission #1215995

#	Time	Username	Problem	Language	Result	Execution time	Memory
1215995		AmirAli_H1	Meetings (JOI19_meetings)	C++20	100 / 100	701 ms	5064 KiB

meetings

// In the name of Allah

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

typedef		long long int			ll;
typedef		long double				ld;
typedef		pair<int, int>			pii;
typedef		pair<ll, ll>			pll;
typedef		complex<ld>				cld;

#define		all(x)					(x).begin(),(x).end()
#define		len(x)					((ll) (x).size())
#define		F						first
#define		S						second
#define		pb						push_back
#define		sep						' '
#define		endl					'\n'
#define		Mp						make_pair
#define		kill(x)					cout << x << '\n', exit(0)
#define		set_dec(x)				cout << fixed << setprecision(x);
#define		file_io(x,y)			freopen(x, "r", stdin); freopen(y, "w", stdout);
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());

const int maxn = 2000 + 4;

int n;
vector<int> adj[maxn];
int M[maxn], mark[maxn];
int sz[maxn], h[maxn];
vector<int> ls[maxn], lsx;

void pre_dfs(int v, int p, int d) {
	sz[v] = 1; h[v] = d;
	for (int u : adj[v]) {
		if (mark[u] || u == p) continue;
		pre_dfs(u, v, d + 1);
		sz[v] += sz[u];
	}
}

int get_cent(int v, int p, int SZ) {
	for (int u : adj[v]) {
		if (mark[u] || u == p) continue;
		if (sz[u] * 2 > SZ) return get_cent(u, v, SZ);
	}
	return v;
}

void dfsx(int v, int p, int R) {
	ls[R].pb(v);
	for (int u : adj[v]) {
		if (mark[u] || u == p) continue;
		dfsx(u, v, R);
	}
}

bool cmp(int u, int v) {
	return (len(ls[u]) > len(ls[v]));
}

void addE(int u, int v) {
	adj[u].pb(v); adj[v].pb(u);
	M[u] = 1; M[v] = 1;
}

void delE(int u, int v) {
	adj[u].erase(find(all(adj[u]), v));
	adj[v].erase(find(all(adj[v]), u));
}

void addV(int u1, int u2, int v) {
	delE(u1, u2); addE(u1, v); addE(v, u2);
}

int fixV(int rt, int v, int u, int x) {
	mark[v] = 1;
	for (int w : lsx) {
		if (w == u) continue;
		for (int f : ls[w]) mark[f] = 1;
	}
	if (h[u] > h[v]) return u;
	else return rt;
}

void addx(int rt, int x) {
	pre_dfs(rt, -1, 0);
	int v = get_cent(rt, -1, sz[rt]);
	lsx.clear(); ls[v].clear();
	for (int u : adj[v]) {
		if (mark[u]) continue;
		ls[u].clear(); dfsx(u, v, u);
		lsx.pb(u);
	}
	sort(all(lsx), cmp);
	if (len(lsx) % 2 == 1) lsx.pb(v);
	for (int i = 0; i < len(lsx); i += 2) {
		int u1 = lsx[i], u2 = lsx[i + 1];
		int R = Query(u1, u2, x);
		if (R == v) continue;
		if (R == x) {
			if (u2 == v || Query(v, u1, x) == x) addV(v, u1, x);
			else addV(v, u2, x);
		}
		else if (R == u1) addx(fixV(rt, v, u1, x), x);
		else if (R == u2) addx(fixV(rt, v, u2, x), x);
		else {
			if (u2 == v || Query(v, u1, x) == R) {
				addV(v, u1, R); addE(R, x);
			}
			else {
				addV(v, u2, R); addE(R, x);
			}
		}
		return ;
	}
	addE(v, x);
	return ;
}

void Solve(int N) {
	n = N;
	int vx = 0; M[vx] = 1;
	for (int v = 0; v < n; v++) {
		if (M[v]) continue;
		for (int i = 0; i < n; i++) mark[i] = (1 - M[i]);
		addx(vx, v);
	}
	for (int u = 0; u < n; u++) {
		for (int v : adj[u]) {
			if (v <= u) continue;
			Bridge(u, v);
		}
	}
}

• Subtask 1: 7 / 7
• Subtask 2: 10 / 10
• Subtask 3: 12 / 12
• Subtask 4: 71 / 71