Submission #1066206

#	Time	Username	Problem	Language	Result	Execution time	Memory
1066206		Nonoze	Regions (IOI09_regions)	C++17	18 / 100	1796 ms	131076 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)

// #define int long long
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;
}


struct SegTree {
	int n, k;
	vector<map<int, int>> t;
	SegTree(int _n, int _k) {
		n=_n, k=_k;
		t.resize(4*n);
	}
	void build(int v, int tl, int tr, vector<int>& a) {
		if (tl==tr) {
			t[v][a[tl]]=1;
			return;
		}
		int tm=(tl+tr)/2;
		build(2*v, tl, tm, a);
		build(2*v+1, tm+1, tr, a);
		for (auto u: t[2*v]) t[v][u.fi]+=u.se;
		for (auto u: t[2*v+1]) t[v][u.fi]+=u.se;
	}
	int query(int v, int tl, int tr, int l, int r, int val) {
		if (l>r) return 0;
		if (tl==l && tr==r) return t[v][val];
		int tm=(tl+tr)/2;
		return query(2*v, tl, tm, l, min(r, tm), val)+query(2*v+1, tm+1, tr, max(l, tm+1), r, val);
	}
};

int n, k, m=0, q, SQRT;
vector<int> a, in, out, tobuild;
vector<vector<int>> adj, calc;
string s;

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

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

void solve() {
	read(n, k, q); SQRT=sqrt(n);
	a.clear(), a.resize(n), adj.clear(), adj.resize(n);
	vector<int> cnt(k, 0);
	vector<vector<int>> nodes(k);
	in.clear(), in.resize(n), out.clear(), out.resize(n);
	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);
	}
	SegTree st(n, k);
	dfs(0);
	st.build(1, 0, n-1, tobuild);
	calc.resize(k);
	for (int i=0; i<k; i++) {
		if (cnt[i]>=SQRT) {
			calc[i].resize(k);
			dfs(0, i, 0);
		}
	}
	while (q--) {
		int u, v; read(u, v); u--, v--;
		if (cnt[u]>=SQRT) {
			cout << calc[u][v] << endl;
			continue;
		}
		int ans=0;
		for (auto x: nodes[u]) {
			ans+=st.query(1, 0, n-1, in[x], out[x]-1, v);
		}
		cout << ans << endl;
	}
}

• Subtask 1: 13 / 15
• Subtask 2: 5 / 85