Submission #1066286

#	Time	Username	Problem	Language	Result	Execution time	Memory
1066286		Nonoze	Regions (IOI09_regions)	C++17	100 / 100	3581 ms	28284 KiB

regions

/*
*	Author: Nonoze
*	Created: Monday 19/08/2024
*/
#include <bits/stdc++.h>
using namespace std;

#ifndef _IN_LOCAL
	#define dbg(...)
#endif

// #define endl '\n'
#define endlfl '\n' << flush
#define quit(x) return (void)(cout << x << endl)

template<typename T> void read(T& x) { cin >> x;}
template<typename T1, typename T2> void read(pair<T1, T2>& p) { read(p.first), read(p.second);}
template<typename T> void read(vector<T>& v) { for (auto& x : v) read(x); }
template<typename T1, typename T2> void read(T1& x, T2& y) { read(x), read(y); }
template<typename T1, typename T2, typename T3> void read(T1& x, T2& y, T3& z) { read(x), read(y), read(z); }
template<typename T1, typename T2, typename T3, typename T4> void read(T1& x, T2& y, T3& z, T4& zz) { read(x), read(y), read(z), read(zz); }
template<typename T> void print(vector<T>& v) { for (auto& x : v) cout << x << ' '; cout << endl; }

#define sz(x) (int)(x.size())
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
#define pb push_back
#define mp make_pair
#define fi first
#define se second
#define cmin(a, b) a = min(a, b)
#define cmax(a, b) a = max(a, b)

const int inf = numeric_limits<int>::max() / 4;
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
const int MOD = 1e9+7, LOG=25;



void solve();

signed main() {
	ios::sync_with_stdio(0);
	cin.tie(0);
	int tt=1;
	// cin >> tt;
	while(tt--) solve();
	return 0;
}

int n, k, m=-1, q, SQRT;
vector<int> a, in, out, cnt;
vector<vector<int>> adj, calc, calc2, empls;
string s;

void dfs(int u, int i, int comp) {
	if (a[u]==i) comp++;
	else calc[i][a[u]]+=comp;
	for (auto v: adj[u]) dfs(v, i, comp);
}

int dfs2(int u, int i) {
	int comp=0;
	for (auto v: adj[u]) comp+=dfs2(v, i);
	if (a[u]==i) comp++;
	else calc2[i][a[u]]+=comp;
	return comp;
}

void dfs(int u) {
	in[u]=++m;
	if (cnt[a[u]]<SQRT) empls[a[u]].pb(m);
	for (auto v: adj[u]) dfs(v);
	out[u]=m;
}

void solve() {
	read(n, k, q); SQRT=sqrt(n)*5;
	a.resize(n), adj.resize(n), in.resize(n), out.resize(n), cnt.resize(k, 0), empls.resize(k);
	vector<vector<int>> nodes(k);
	for (int i=0; i<n; i++) {
		if (i) {
			int x; read(x); x--;
			adj[x].pb(i);
		}
		read(a[i]); a[i]--; cnt[a[i]]++;
		nodes[a[i]].pb(i);
	}
	dfs(0);
	calc.resize(k), calc2.resize(k);
	for (int i=0; i<k; i++) {
		if (cnt[i]>=SQRT) {
			calc[i].resize(k), calc2[i].resize(k);
			dfs(0, i, 0);
			dfs2(0, i);
		}
	}
	while (q--) {
		int u, v; read(u, v); u--, v--;
		if (cnt[u]>=SQRT) {
			cout << calc[u][v] << endl;
			continue;
		} else if (cnt[v]>=SQRT) {
			cout << calc2[v][u] << endl;
			continue;
		}
		int ans=0;
		for (auto x: nodes[u]) {
			auto it1=lower_bound(all(empls[v]), in[x]);
			auto it2=upper_bound(all(empls[v]), out[x]);
			ans+=it2-it1;
		}
		cout << ans << endl;
	}
}

• Subtask 1: 15 / 15
• Subtask 2: 85 / 85