Submission #1137117

#	Time	Username	Problem	Language	Result	Execution time	Memory
1137117		lucaskojima	Regions (IOI09_regions)	C++17	55 / 100	8100 ms	26520 KiB

regions

#include "bits/stdc++.h"
#define ff first
#define ss second
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
#define sz(x) (int)(x).size()

using namespace std;
using ll = long long;
using pii = pair<int, int>;

const char nl = '\n';
const ll LINF = 0x3f3f3f3f3f3f3f3f;
const int INF = 0x3f3f3f3f;

int main() {
	ios::sync_with_stdio(0), cin.tie(0);

	int N, R, Q; cin >> N >> R >> Q;

	vector<vector<int>> adj(N + 1);
	vector<int> r(N + 1);

	for (int i = 1; i <= N; i++) {
		if (i == 1) {
			int a; cin >> a;
			r[i] = a;
		} else {
			int a, b; cin >> a >> b;
			adj[a].push_back(i);
			adj[i].push_back(a);
			r[i] = b;
		}
	}

	vector<vector<int>> emp(R + 1);
	vector<int> tin(N + 1), tout(N + 1);
	int tcur = 0;

	auto euler = [&](auto euler, int x, int p) -> void {
		tin[x] = ++tcur;
		emp[r[x]].push_back(x);

		for (int k : adj[x]) {
			if (k == p) continue;
			euler(euler, k, x);
		}
		tout[x] = tcur;
	}; euler(euler, 1, -1);

	while (Q--) {
		int a, b; cin >> a >> b;

		vector<pii> line;
		for (int x : emp[a]) {
			line.push_back({tin[x], 1});
			line.push_back({tout[x], 3});
		}
		for (int y : emp[b])
			line.push_back({tin[y], 2});

		sort(all(line));

		int ans = 0, cnt = 0;
		for (auto [d, t] : line) {
			if (t == 1) cnt++;
			if (t == 2) ans += cnt;
			if (t == 3) cnt--;
		}

		cout << ans << endl;
	}
	return 0;
}

• Subtask 1: 15 / 15
• Subtask 2: 40 / 85