Cod sursa(job #2788002)

Utilizator TudosieRazvanTudosie Marius-Razvan TudosieRazvan Data 24 octombrie 2021 16:49:41
Problema Range minimum query Scor 20
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.1 kb
#include <fstream>
#include <climits>
#include <vector>
#include <queue>
#include <set>
#include <stack>
#include <cstring>
#include<algorithm>

using namespace std;


int n, q;
const int LOG = 19;
int a[100001][LOG];

ifstream fin("rmq.in");
ofstream fout("rmq.out");

void calc()
{
	for (int j = 1; j <= LOG; j++)
	{
		for (int i = 1; i + (1 << j) - 1 <= n; i++)
		{
			//secventa de la i la i+1<<j are minimul
			//egal cu minimul de la i si secv 1<<(j-1) si i+1<<(j-1)
			//concret pt indicele 4 luat de secv 2 avem minimul de la 4 si minimul de la 4+1 ambele luate de lungime 1 
			a[i][j] = min(a[i][j - 1], a[i + (1 << (j - 1))][j - 1]);
		}
	}
}

int query(int L, int R)
{
	int lung = R - L + 1;
	//calculez cea mai mare pputere de 2 care incape in lung;
	int k = 1;
	while (1 << (k + 1) <= lung)
	{
		k++;
	}


	return min(a[L][k], a[R - (1 << k) + 1][k]);
}

int main()
{
	fin >> n >> q;
	for (int i = 1; i <= n; i++)
	{
		fin >> a[i][0];
	}
	calc();
	for (int i = 1; i <= q; i++)
	{
		int x, y;
		fin >> x >> y;
		fout << query(x, y) << "\n";
	}
	return 0;
}