Cod sursa(job #3142405)

Utilizator EricDimiC. Eric-Dimitrie EricDimi Data 21 iulie 2023 10:13:43
Problema Range minimum query Scor 70
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 0.86 kb
#include <iostream>
#include <fstream>
#define NMAX 100'000

using namespace std;

ifstream f("rmq.in");
ofstream g("rmq.out");

const int LOG = 17;
int logaritm_binar[NMAX], a[NMAX], rmq[NMAX][LOG];
int n, q, i, k, j, st, dr;

int query(int st, int dr)
{
	int l = dr - st + 1, k = logaritm_binar[l];
	return min(rmq[st][k], rmq[dr - (1 << k) + 1][k]);
}

int main()
{
	f >> n >> q;

	logaritm_binar[1] = 0;
	for (i = 2; i <= n; i++)
		logaritm_binar[i] = logaritm_binar[i / 2] + 1;

	for (i = 1; i <= n; i++)
	{
		f >> a[i];
		rmq[i][0] = a[i];
	}

	for (k = 1; k < LOG; k++)
	for (i = 1; i + (1 << k) - 1 <= n; i++)
		rmq[i][k] = min(rmq[i][k - 1], rmq[i + (1 << (k - 1))][k - 1]);

	for (i = 1; i <= q; i++)
	{
		f >> st >> dr;
		g << query(st, dr) << "\n";
	}

	/// O(n log2(n) + Q)

    f.close();
    g.close();
    return 0;
}