Submission #1033975

#	Time	Username	Problem	Language	Result	Execution time	Memory
1033975		AmirAli_H1	Split the Attractions (IOI19_split)	C++17	100 / 100	78 ms	37572 KiB

split

// In the name of Allah

#include <bits/stdc++.h>
#include "split.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 = 3e5 + 7;

int n, m, R;
vector<int> adj[maxn], adjx[maxn];
vector<pii> E, Ex; vector<int> res;
int mark[maxn], p[maxn], sz[maxn];
vector<int> A, arr, val;

bool cmp(int i, int j) {
	return (A[i] < A[j]);
}

void pre_dfs(int v, int par = -1) {
	mark[v] = 1;
	p[v] = par; sz[v] = 1;
	for (int u : adj[v]) {
		if (!mark[u]) {
			pre_dfs(u, v);
			sz[v] += sz[u];
			Ex.pb(Mp(v, u));
		}
	}
}

int get_cent(int v) {
	for (int u : adj[v]) {
		if (p[u] != v) continue;
		if (sz[u] * 2 > n) return get_cent(u);
	}
	return v;
}

int get(int a) {
	return (p[a] == a) ? a : p[a] = get(p[a]);
}

void merge(int u, int v) {
	int a = get(u), b = get(v);
	if (a == b) return ;
	if (sz[a] > sz[b]) {
		swap(u, v); swap(a, b);
	}
	p[a] = b; sz[b] += sz[a]; sz[a] = 0;
	adjx[u].pb(v); adjx[v].pb(u);
}

int get_vx(int v) {
	iota(p, p + n, 0); fill(sz, sz + n, 1);
	for (auto f : Ex) {
		if (f.F == v || f.S == v) continue;
		merge(f.F, f.S);
	}
	for (int i = 0; i < n; i++) {
		if (i == v || get(i) != i) continue;
		if (sz[i] >= val[0] && sz[i] <= val[0] + val[2]) return i;
	}
	for (auto f : E) {
		if (f.F == v || f.S == v) continue;
		merge(f.F, f.S); int i = get(f.F);
		if (sz[i] >= val[0] && sz[i] <= val[0] + val[2]) return i;
	}
	return -1;
}

void dfs_res(int v, int c) {
	mark[v] = 1;
	res[v] = c; R--;
	if (R == 0) return ;
	for (int u : adj[v]) {
		if (!mark[u]) {
			dfs_res(u, c);
			if (R == 0) return ;
		}
	}
}

vector<int> find_split(int Nx, int a, int b, int c, vector<int> ux, vector<int> vx) {
	n = Nx; m = len(ux); A = {a, b, c};
	arr = {0, 1, 2}; sort(all(arr), cmp);
	val = {A[arr[0]], A[arr[1]], A[arr[2]]};
	res.clear(); res.resize(n);
	
	for (int i = 0; i < m; i++) {
		int u = ux[i], v = vx[i];
		adj[u].pb(v); adj[v].pb(u);
		E.pb(Mp(u, v));
	}
	
	Ex.clear(); pre_dfs(0);
	int v = get_cent(0);
	int u = get_vx(v);
	if (u == -1) return res;
	
	fill(mark, mark + n, 0);
	fill(all(res), arr[2] + 1);
	for (int i = 0; i < n; i++) swap(adj[i], adjx[i]);
	R = val[0]; dfs_res(u, arr[0] + 1);
	for (int i = 0; i < n; i++) swap(adj[i], adjx[i]);
	R = val[1]; dfs_res(v, arr[1] + 1);
	
	return res;
}

• Subtask 1: 7 / 7
• Subtask 2: 11 / 11
• Subtask 3: 22 / 22
• Subtask 4: 24 / 24
• Subtask 5: 36 / 36