Submission #248579

#	Time	Username	Problem	Language	Result	Execution time	Memory
248579		mode149256	Regions (IOI09_regions)	C++14	100 / 100	3274 ms	40312 KiB

regions

/*input
6 3 4
1
1 2
1 3
2 3
2 3
5 1
1 2
1 3
2 3
3 1
*/
#include <bits/stdc++.h>
#pragma GCC optimize("Ofast")
using namespace std;

namespace my_template {
typedef long long ll;
typedef long double ld;
typedef complex<ld> cd;

typedef pair<int, int> pi;
typedef pair<ll, ll> pl;
typedef pair<ld, ld> pd;

typedef vector<int> vi;
typedef vector<vi> vii;
typedef vector<ld> vd;
typedef vector<ll> vl;
typedef vector<vl> vll;
typedef vector<pi> vpi;
typedef vector<vpi> vpii;
typedef vector<pl> vpl;
typedef vector<cd> vcd;
typedef vector<pd> vpd;
typedef vector<bool> vb;
typedef vector<vb> vbb;
typedef std::string str;
typedef std::vector<str> vs;

#define x first
#define y second
#define debug(...) cout<<"["<<#__VA_ARGS__<<": "<<__VA_ARGS__<<"]\n"

const ld PI = 3.14159265358979323846264338327950288419716939937510582097494L;

template<typename T>
pair<T, T> operator+(const pair<T, T> &a, const pair<T, T> &b) { return pair<T, T>(a.x + b.x, a.y + b.y); }
template<typename T>
pair<T, T> operator-(const pair<T, T> &a, const pair<T, T> &b) { return pair<T, T>(a.x - b.x, a.y - b.y); }
template<typename T>
T operator*(const pair<T, T> &a, const pair<T, T> &b) { return (a.x * b.x + a.y * b.y); }
template<typename T>
T operator^(const pair<T, T> &a, const pair<T, T> &b) { return (a.x * b.y - a.y * b.x); }

template<typename T>
void print(vector<T> vec, string name = "") {
	cout << name;
	for (auto u : vec)
		cout << u << ' ';
	cout << '\n';
}
}
using namespace my_template;

const int MOD = 1000000007;
const ll INF = std::numeric_limits<ll>::max();
const int MX = 200101;

int N, R, Q;
vi edges[MX];
vi kas;
vii kokie;

vi timeIn;
vi timeOut;
vi atgal;
vi sz;
vi indeks;
vii ats;
vii revAts;
int piv = 0;
int sqr;

int dfs(int x) {
	atgal[piv] = x;
	timeIn[x] = piv++;
	sz[x] = 1;
	for (auto u : edges[x])
		sz[x] += dfs(u);

	timeOut[x] = piv;
	return sz[x];
}

void precompute() {
	piv = 0;
	for (int r = 1; r <= R; ++r)
	{
		if ((int)kokie[r].size() < sqr) continue;

		indeks[r] = piv;
		ats.emplace_back(vi(R + 1, 0));
		revAts.emplace_back(vi(R + 1, 0));

		vi sum(N + 1, 0);
		for (int i = 0; i < N; ++i)
			sum[i] = (kas[atgal[i]] == r) + (i ? sum[i - 1] : 0);

		for (int i = 0; i < N; ++i)
		{
			int c = atgal[i]; // node
			revAts[piv][kas[c]] += sum[timeOut[c] - 1] - (timeIn[c] ? sum[timeIn[c] - 1] : 0);
		}

		vi plius(N + 1, 0);
		for (auto u : kokie[r]) {
			plius[u]++;
			plius[timeOut[atgal[u]]]--;
		}

		for (int i = 0; i < N; ++i)
		{
			plius[i] += (i ? plius[i - 1] : 0);
			ats[piv][kas[atgal[i]]] += plius[i];
		}

		piv++;
	}
}

int main() {
	ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
	cin >> N >> R >> Q;
	kas.resize(N + 1);
	kokie.resize(R + 1);
	timeIn.resize(N + 1);
	timeOut.resize(N + 1);
	sz.resize(N + 1);
	atgal.resize(N + 1);
	indeks.resize(N + 1);

	sqr = (int)sqrt(N);

	cin >> kas[1];
	kokie[kas[1]].emplace_back(1);

	for (int i = 2; i <= N; ++i)
	{
		int a; cin >> a >> kas[i];
		edges[a].push_back(i);
		kokie[kas[i]].emplace_back(i);
	}

	dfs(1);

	for (auto && vec : kokie) {
		for (auto && u : vec)
			u = timeIn[u];

		sort(vec.begin(), vec.end());
	}
	precompute();

	for (int i = 0; i < Q; ++i)
	{
		int r1, r2;
		cin >> r1 >> r2;
		int cnt = 0;

		if ((int)kokie[r1].size() >= sqr) {
			cout << ats[indeks[r1]][r2] << endl;
		} else if ((int)kokie[r2].size() >= sqr) {
			cout << revAts[indeks[r2]][r1] << endl;
		} else {
			stack<int> uzdaryt;

			int j1 = 0;

			int c = 0;
			for (auto u : kokie[r2]) {
				while (uzdaryt.size() and uzdaryt.top() <= u) {
					c--;
					uzdaryt.pop();
				}
				while (j1 < (int)kokie[r1].size() and kokie[r1][j1] <= u) {
					uzdaryt.push(timeOut[atgal[ kokie[r1][j1] ]]);
					c++;
					j1++;
					while (uzdaryt.size() and uzdaryt.top() <= u) {
						c--;
						uzdaryt.pop();
					}
				}

				cnt += c;
			}

			cout << cnt << endl;
		}
	}
}

/* Look for:
* special cases (n=1?)
* overflow (ll vs int?)
* the exact constraints (multiple sets are too slow for n=10^6 :( )
* array bounds
*/

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