Cod sursa(job #717097)

Utilizator rares192Preda Rares Mihai rares192 Data 19 martie 2012 17:41:30
Problema Range minimum query Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.23 kb
#include<fstream>
#include<algorithm>
using namespace std;

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

#define NMAX 100002
#define LMAX 18

long m, n;
long a[NMAX];
long rmq[LMAX][NMAX], lg[NMAX];

int main()
{
	long int i, j, l;
	
	fin >> n >> m;
	for(i = 1; i <= n; ++i)
		fin >> a[i];
	
	//calculez puterile de 2..care e puterea maxima a lui 2 pana la i
	//ex 7 = 2, 16=4, 3 = 1 s.a.m.d
	lg[1] = 0;
	for(i = 2; i <= n; ++i)
		lg[i] = lg[i/2] + 1;
	
	//initializam matricea..prima linie 
	for( i = 1; i <= n; ++i)
		rmq[0][i] = a[i];
	
	// a[i][j]  reprezinta cel mai mic nr care incepe de la pozitia
	// j si are lungimea 2^i
	for( i = 1; (1 << i) <= n; ++i)
		for( j = 1; j <= n - (1 << i)+1; ++j)
		{
			l = 1 << (i-1);
			rmq[i][j] = min( rmq[i-1][j], rmq[i-1][j+l] );
		}
		
	long x, y, dif, sh;
	for( i = 1; i <= m; ++i)
	{
		fin >> x >> y;
		dif = (y-x)+1;            //nr de elemente din intervalul x y
		l = lg[dif]; 	          
		sh = dif - (1 << l);
		fout << min(rmq[l][x], rmq[l][x+sh]) << "\n";
	}
	
		
/*		
	fout << endl;
	for(i = 0; i <= 5; ++i)
	{
		for( j = 0; j <= 5; ++j)
			fout << rmq[i][j] << " ";
	fout << endl;
	}
*/	
	
	fin.close();
	fout.close();
	return 0;
}