Submission #365101

#	Time	Username	Problem	Language	Result	Execution time	Memory
365101		crackersamdjam	Regions (IOI09_regions)	C++17	95 / 100	8010 ms	110748 KiB

regions

#include <bits/stdc++.h>
#define all(x) (x).begin(), (x).end()

#ifndef ONLINE_JUDGE
template<typename T>
void pr(T a){std::cerr<<a<<std::endl;}
template<typename T,typename... Args>
void pr(T a, Args... args) {std::cerr<<a<<' ',pr(args...);}
#else
template<typename... Args>
void pr(Args... args){}
#endif

using namespace std;
using ll = long long;
const int MM = 2e5+5, SQ = 500;

int n, m, q;
int val[MM];
vector<int> adj[MM];
int in[MM], out[MM], t;
map<int, ll> cnt[MM], parcnt;
vector<int> nodes[MM];
int bit[MM];

map<pair<int, int>, ll> ans;
vector<int> big, smol;

void update(int i, int v){
	for(; i < MM; i += i&-i)
		bit[i] += v;
}

int query(int i){
	int v = 0;
	for(; i; i -= i&-i)
		v += bit[i];
	return v;
}

void dfs(int cur, int pre){
	in[cur] = ++t;
	if(size(nodes[val[cur]]) <= SQ){
		for(int i: big)
			ans[{i, val[cur]}] += parcnt[i];
	}
	parcnt[val[cur]]++;

	int id = 0;
	for(auto u: adj[cur]){
		if(u == pre) continue;
		dfs(u, cur);
		if(size(cnt[u]) > size(cnt[id]))
			id = u;
	}
	cnt[cur] = move(cnt[id]);
	for(auto u: adj[cur]){
		if(u == pre) continue;
		if(u != id){
			for(auto [a, c]: cnt[u]){
				cnt[cur][a] += c;
			}
			cnt[u].clear();
			// cnt[u].shrink_to_fit();
		}
	}
	cnt[cur][val[cur]]++;

	if(size(nodes[val[cur]]) <= SQ){
		for(int i: big)
			ans[{val[cur], i}] += cnt[cur][i];
	}
	else{
		//big to big 
		for(int i: big){
			ans[{val[cur], i}] += cnt[cur][i];
		}
	}

	parcnt[val[cur]]--;
	out[cur] = t;
}

int main(){
	cin>>n>>m>>q;
	cin>>val[1];
	nodes[val[1]].emplace_back(1);
	for(int i = 2,p; i <= n; i++){
		cin>>p>>val[i];
		adj[p].emplace_back(i);
		nodes[val[i]].emplace_back(i);
	}
	for(int i = 1; i <= m; i++){
		if(size(nodes[i]) > SQ){
			big.emplace_back(i);
		}
		else{
			smol.emplace_back(i);
		}
	}
	dfs(1, 0);
	for(int i = 0,a,b; i < q; i++){
		cin>>a>>b;
		// assert(a != b);
		if(size(nodes[a]) > SQ or size(nodes[b]) > SQ){
			cout<<ans[{a, b}]<<'\n';
		}
		else{
			for(int j: nodes[b])
				update(in[j], 1);
			ll ret = 0;
			for(int j: nodes[a])
				ret += query(out[j]) - query(in[j]-1);
			for(int j: nodes[b])
				update(in[j], -1);
			cout<<ret<<'\n';
		}
	}
}
/*
I need online solution...
I precompute all small-large and all large-large

smol-smol ac
big-big ac
big-smol wa

*/

• Subtask 1: 15 / 15
• Subtask 2: 80 / 85