제출 #477615

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
477615		Abrar_Al_Samit	Regions (IOI09_regions)	C++17	35 / 100	8101 ms	43816 KiB

regions

#pragma GCC optimize("Ofast")
#include<bits/stdc++.h>
using namespace std;
const int MX = 200005;
struct FenwickTree {
    vector<int> bit;  // binary indexed tree
    int n = MX;

    int sum(int r) {
    	if(bit.empty()) bit.resize(n);
        int ret = 0;
        for (; r >= 0; r = (r & (r + 1)) - 1)
            ret += bit[r];
        return ret;
    }

    int sum(int l, int r) {
        return sum(r) - sum(l - 1);
    }

    void add(int idx, int delta) {
    	if(bit.empty()) bit.resize(n);
        for (; idx < n; idx = idx | (idx + 1))
            bit[idx] += delta;
    }
};
const int B = 400;
int N, R, Q;
vector <int> g[MX], region[MX];
int H[MX], st[MX], en[MX], timer=1, stwho[MX];
map <int, vector <long long>> prep;
void Flat(int v, int p) {
	stwho[timer] = v;
	st[v] = timer++;
	region[H[v]].push_back(st[v]);
	for(auto to : g[v]) if(to!=p) {
		Flat(to, v);
	}
	en[v] = timer-1;
}
int main() {
	cin >> N >> R >> Q;
	cin >> H[1];
	for(int i=2; i<=N; ++i) {
		int p; cin >> p >> H[i];
		g[p].push_back(i);
	}
	Flat(1, 1);
	vector <int> bigs;
	for(int i=1; i<=R; ++i) if(region[i].size()>B) {
		bigs.push_back(i);
	}
	FenwickTree A; 
	for(int all=1; all<=R; ++all) {
		for(auto it : region[all]) {
			A.add(st[it], 1);
		}
		for(auto b : bigs) {
			if(prep[b].empty()) prep[b].resize(R+1);
			for(auto it : region[b]) {
				prep[b][all] += A.sum(st[it], en[it]);
			}
		}
		for(auto it : region[all]) {
			A.add(st[it], -1);
		}
	}

	// O(Q(rootNlogN + logR))
	while(Q--) {
		int r1, r2;
		cin >> r1 >> r2;
		long long ans = 0;
		if(region[r1].size()>B) {
			ans = prep[r1][r2];
		} else {
			for(auto p1 : region[r1]) {
				auto it = upper_bound(region[r2].begin(), region[r2].end(), en[stwho[p1]]);
				auto it2 = lower_bound(region[r2].begin(), region[r2].end(), p1);
				ans += it-it2; 
			}
		}
		cout << ans << endl;
	}
	return 0;
}

• Subtask 1: 15 / 15
• Subtask 2: 20 / 85