Submission #883407

#	Time	Username	Problem	Language	Result	Execution time	Memory
883407		serifefedartar	Regions (IOI09_regions)	C++17	100 / 100	4125 ms	49512 KiB

regions

#include <bits/stdc++.h>
using namespace std;
 
#define fast ios::sync_with_stdio(0);cin.tie(0);
#define s second
#define f first
typedef long long ll;
const ll MOD = 1e9 + 9;
const ll LOGN = 21;
const ll MAXN = 2e5 +  100;
 
vector<vector<int>> graph;
int reg[MAXN], dp[505][505];
vector<int> cnt[MAXN], Rin[25100], Rout[25100], plc[25100];
map<pair<int,int>, pair<int,bool>> memo;
 
void dfs(int node, int parent) {
	cnt[node][reg[node]]++;
	for (int reg_other = 1; reg_other <= 500; reg_other++)
		dp[reg_other][reg[node]] += cnt[node][reg_other];
	for (auto u : graph[node]) {
		swap(cnt[u], cnt[node]);
		dfs(u, node);
	}
	cnt[node][reg[node]]--;
	swap(cnt[parent], cnt[node]);
}
	
int T = 0;
int tin[MAXN], tout[MAXN];
void dfs2(int node, int parent) {
	tin[node] = ++T;
	Rin[reg[node]].push_back(tin[node]);
	for (auto u : graph[node])
		dfs2(u, node);
	tout[node] = ++T;
	Rout[reg[node]].push_back(tout[node]);
}
 
int main() {
	fast
	int N, R, Q, a, b;
	cin >> N >> R >> Q;
 
	graph = vector<vector<int>>(N+1, vector<int>());
	cin >> reg[1];
	plc[reg[1]].push_back(1);
	for (int i = 2; i <= N; i++) {
		int S;
		cin >> S >> reg[i];
		plc[reg[i]].push_back(i);
		graph[S].push_back(i);
	}
 
	if (R <= 500) {
		cnt[1] = vector<int>(505, 0);
		dfs(1, 1);
		for (int i = 0; i < Q; i++) {
			cin >> a >> b;
			cout << dp[a][b] << endl;
		}
	} else {
		dfs2(1, 1);
		for (int i = 1; i <= R; i++) {
			sort(Rin[i].begin(), Rin[i].end());
			sort(Rout[i].begin(), Rout[i].end());
		}
 
		for (int i = 0; i < Q; i++) {
			cin >> a >> b;
			if (memo[{a, b}].s == false) {
				int ans = 0;
				if (plc[a].size() < plc[b].size())
					for (auto u : plc[a])
						ans += (upper_bound(Rin[b].begin(), Rin[b].end(), tout[u]) - Rin[b].begin()) - (upper_bound(Rin[b].begin(), Rin[b].end(), tin[u]) - Rin[b].begin());
				else
					for (auto u : plc[b])
						ans += (upper_bound(Rin[a].begin(), Rin[a].end(), tin[u]) - Rin[a].begin()) - (upper_bound(Rout[a].begin(), Rout[a].end(), tin[u]) - Rout[a].begin());
				memo[{a, b}] = {ans, 1};
			}
			cout << memo[{a, b}].f << endl;
		}
	}
}

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