Submission #1275923

#	Time	Username	Problem	Language	Result	Execution time	Memory
1275923		sonarcht	Regions (IOI09_regions)	C++20	29 / 100	8036 ms	44864 KiB

regions

#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
#define ll int
typedef pair<ll,ll> pll; typedef vector<ll> vll; typedef map<ll,ll> mll;
mt19937_64 rng(chrono::high_resolution_clock().now().time_since_epoch().count());
const ll maxn = 2e5 + 6, maxr = 25e3 + 6, maxb = sqrt(25e3) + 6, mod = 1e9 + 7;
ll n, m, r, k, q, ans, a[maxn], block;

vll adj[maxn];
ll tin[maxn], tout[maxn], tour[maxn], timer = 0;
void dfs(ll p, ll u) {
	tin[u] = ++timer;
	tour[timer] = u;
	for (ll v : adj[u]) {
		if (v == p) continue;
		dfs(u,v);
	}
	tout[u] = timer;
}

vll v[maxn], mp[maxn];
ll get(ll l, ll r, ll k) {
	auto &v = mp[k];
	return upper_bound(v.begin(), v.end(), r) - lower_bound(v.begin(), v.end(), l);
}

vll heavy = {0};
ll pos[maxn], freq[maxn], f[maxb][maxr];
void preprocess() {
	for (int i = 1; i <= n; ++i) ++freq[a[i]];
	for (int i = 1; i <= r; ++i) {
		if (freq[i] <= block) continue;
		pos[i] = heavy.size();
		heavy.push_back(i);
	}
	//for (ll i : heavy) cout << i << " "; cout << endl;
	m = heavy.size() - 1;
	for (int i = 1; i <= n; ++i) v[a[i]].push_back(i);
	for (int i = 1; i <= n; ++i) mp[a[tour[i]]].push_back(i);
	for (int i = 1; i <= m; ++i) {
		//cout << "i: " << heavy[i] << endl;
		for (int j = 1; j <= r; ++j) {
			ll res = 0;
			for (ll node : v[heavy[i]]) res += get(tin[node], tout[node], j);
			f[i][j] = res;
			//cout << "j: " << j << " " << f[i][j] << endl;
		}
	}
}

void solve() {
	cin >> n >> r >> q;
	block = sqrt(r);
	cin >> a[1];
	for (int i = 2; i <= n; ++i) {
		ll y;
		cin >> y >> a[i];
		adj[i].push_back(y);
		adj[y].push_back(i);
	}
	dfs(-1,1);
	preprocess();
	//for (int i = 1; i <= n; ++i) cout << a[tour[i]] << " "; cout << endl;
	// for (int i = 1; i <= r; ++i) {
		// cout << i << ": ";
		// for (ll j : v[i]) cout << j << " "; cout << endl;
	// }
	while (q--) {
		ll x, y;
		cin >> x >> y;
		if (freq[x] > block) {
			//cout << "HEAVY\n";
			cout << f[pos[x]][y] << endl;
		} else {
			//cout << "LIGHT\n";
			ll ans = 0;
			for (auto node : v[x]) ans += get(tin[node], tout[node], y);
			cout << ans << endl;
		}
	}
	return;
}

int main() {
	ios_base::sync_with_stdio(0);
	cin.tie(0);
	if (fopen(".INP", "r")) {
		freopen(".INP", "r", stdin);
		freopen(".OUT", "w", stdout);
	}
	ll testCase = 1;
//	cin >> testCase;
	while (testCase--) {
		solve();
	}
	return 0;
}

Compilation message (stderr)

regions.cpp: In function 'int main()':
regions.cpp:89:24: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   89 |                 freopen(".INP", "r", stdin);
      |                 ~~~~~~~^~~~~~~~~~~~~~~~~~~~
regions.cpp:90:24: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   90 |                 freopen(".OUT", "w", stdout);
      |                 ~~~~~~~^~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 9 / 15
• Subtask 2: 20 / 85