Submission #1156721

#	Time	Username	Problem	Language	Result	Execution time	Memory
1156721		minh30082008	Regions (IOI09_regions)	C++20	100 / 100	3154 ms	35984 KiB

regions

#include<bits/stdc++.h>
#define INF 1e18
#define fi first
#define se second
#define FOR(i, k, n) for(ll i = k; i <= n; i++)
#define FOR1(i, k, n) for(ll i = k; i >= n; i--)
#define pb push_back
#define fastio ios::sync_with_stdio(0); cin.tie(0); cout.tie(0)
#define vi vector<int>
#define pii pair<int, int>
#define vii vector<pii>
#define ll long long
#define vll vector<ll>
#define pll pair<ll, ll>
#define re return 0
#define mii map<int, int>
#define input "chinaflu.inp"
#define output "chinaflu.out"
#define rf 	freopen(input, "r", stdin); freopen(output, "w", stdout)
using namespace std;
const int maxn = 2e5 + 5;
const int mod = 1e9 + 9;
const int base = 998244353;
void add(int &a, int b) 
{
	a += b; 
	if(a >= mod) a -= mod; 
	if(a < 0) a += mod; 
}
mt19937 rd(chrono::steady_clock::now().time_since_epoch().count());
int rand(int l, int r)
{
	return uniform_int_distribution<int>(l, r) (rd);
}
vi adj[maxn];
int tin[maxn], tout[maxn];
int region[maxn], timedfs;
vi vt[maxn];
ll dp[405][25005];
vi vung[25005];
int tmp, cnt, dem, pos[25005];
void DFS(int u, int par)
{
	tin[u] = ++timedfs;
	vt[region[u]].pb(timedfs);
	for(auto v : adj[u])
	{
		if(v == par)
			continue;
		DFS(v, u);
	}
	tout[u] = timedfs;
}
void calc(int u, int par)
{
	dp[cnt][region[u]] += dem;
	if(region[u] == tmp)
		dem++;
	for(auto v : adj[u])
	{
		if(v == par)
			continue;
		calc(v, u);
	}
	if(region[u] == tmp)
		dem--;
}
int main()
{
	fastio;
	int n, r, q;
	cin >> n >> r >> q;
	cin >> region[1];
	vung[region[1]].pb(1);
	FOR(i, 2, n)
	{
		int par;
		cin >> par >> region[i];
		adj[par].pb(i);
		adj[i].pb(par);
		vung[region[i]].pb(i);
	}
	timedfs = 0;
	DFS(1, 0);
	FOR(i, 1, 25000)
		if(vung[i].size() > 500)
		{
			cnt++;
			tmp = i;
			dem = 0;
			pos[i] = cnt;
			calc(1, 0);
		}
	while(q--)
	{
		int u, v;
		cin >> u >> v;
		if(vung[u].size() > 500)
		{
			cout << dp[pos[u]][v] << endl;
			continue;
		}
		ll ans = 0;
		for(auto x : vung[u])
		{
			int l = tin[x];
			int r = tout[x];
			ans += upper_bound(vt[v].begin(), vt[v].end(), r) - upper_bound(vt[v].begin(), vt[v].end(), l);
		}
		cout << ans << endl;
	}
	re;
}

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