Submission #531801

#	Time	Username	Problem	Language	Result	Execution time	Memory
531801		akhan42	Regions (IOI09_regions)	C++17	100 / 100	6587 ms	119236 KiB

regions

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>

using namespace std;
using namespace __gnu_pbds;

#define F first
#define S second
#define forn(i, n) for(int i = 0; i < n; ++i)
#define forbn(i, b, n) for(int i = b; i < n; ++i)
#define sz(v) (int)v.size()
#define pb push_back
#define eb emplace_back
#define all(v) v.begin(), v.end()
#define min3(a, b, c) min(a, min(b, c))

typedef pair<int, int> ii;
typedef vector<int> vi;
typedef vector<ii> vii;
typedef long long ll;
typedef tree<int, null_type, less<int>, rb_tree_tag, tree_order_statistics_node_update> ordered_set;

template <class T> inline void mineq(T &a, T b) { a = min(a, b); }
template <class T> inline void maxeq(T &a, T b) { a = max(a, b); }


const int MX = 200 * 1000 + 10;
const int S = 100;


struct FenwBase {
	int n;
	int bit[MX] = {0};

	void upd(int i, int v) {
		for(i += 1; i <= n; i += i & -i)
			bit[i] += v;
	}

	int psum(int i) {
		int sum = 0;
		for(i += 1; i > 0; i -= i & -i)
			sum += bit[i];
		return sum;
	}
};


struct Fenw {
	FenwBase fb;

	Fenw(int n) {
		fb.n = n;
	}

	void update(int l, int r, int v) {
		fb.upd(l, v);
		fb.upd(r + 1, -v);
	}

	int at(int i) {
		return fb.psum(i);
	}
};


int n, R, Q;
vi gr[MX];
int e2r[MX];
vi r2es[MX];
int pc[S][MX];
int ct[MX];
vi regions;
int inv_reg[MX];
int tin[MX], tout[MX];
int timer = -1;
int pc2[S][MX];
int time2reg[MX];


bool cmp_reg(int r1, int r2) {
	return sz(r2es[r1]) > sz(r2es[r2]);
}


void dfs(int node = 0) {
	forn(i, min(R, S)) {
		int r = regions[i];
		pc[i][e2r[node]] += ct[r];
	}

	tin[node] = ++timer;
	time2reg[timer] = e2r[node];
	ct[e2r[node]] += 1;

	for(int nb: gr[node]) {
		dfs(nb);
	}

	ct[e2r[node]] -= 1;
	tout[node] = timer;
}


void solve() {
	cin >> n >> R >> Q;

	forn(i, n) {
		int r, p;
		if(i == 0) {
			cin >> r;
		} else {
			cin >> p >> r;
			p -= 1;
			gr[p].pb(i);
		}
		r--;
		e2r[i] = r;
		r2es[r].pb(i);
	}

	forn(i, R)
		regions.pb(i);

	sort(all(regions), cmp_reg);

	forn(i, R)
		inv_reg[regions[i]] = i;

	dfs();

	forn(i, min(R, S)) {
		int r = regions[i];

		forn(t, n) {
			pc2[i][t] = (t ? pc2[i][t - 1] : 0) + (time2reg[t] == r ? 1 : 0);
		}
	}

	Fenw fenw(n);

	forn(_, Q) {
		int r1, r2;
		cin >> r1 >> r2;
		r1--; r2--;

		if(inv_reg[r1] < S) {
			cout << pc[inv_reg[r1]][r2] << endl;
		} else if (inv_reg[r2] < S) {
			int sum = 0, i2 = inv_reg[r2];
			for(int node: r2es[r1]) {
				int l = tin[node], r = tout[node];
				sum += pc2[i2][r] - (l ? pc2[i2][l - 1] : 0);
			}
			cout << sum << endl;
		} else {
			int sum = 0;
			for(int node: r2es[r1]) {
				int l = tin[node], r = tout[node];
				fenw.update(l, r, 1);
			}
			for(int node: r2es[r2]) {
				sum += fenw.at(tin[node]);
			}
			cout << sum << endl;
			for(int node: r2es[r1]) {
				int l = tin[node], r = tout[node];
				fenw.update(l, r, -1);
			}
		}
	}
}


int main() {
	ios_base::sync_with_stdio(false);
	cin.tie(nullptr);
	cout.tie(nullptr);

//	freopen("haybales.in", "r", stdin);
//	freopen("haybales.out", "w", stdout);

	int t = 1;
//	cin >> t;
	while(t--) {
		solve();
	}
}

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