Cod sursa(job #1537927)

Utilizator BaweeLazar Vlad Bawee Data 28 noiembrie 2015 12:04:45
Problema Range minimum query Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.15 kb
///SPARSE TABLE ALGORITHM
///PREPROCESARE O(N log2 N)
///QUERY O(1)
#include <fstream>
#include <cmath>

using namespace std;

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

int M[100001][17];
int A[100001];
int N,T;

void preprocesare()
{
    int i,j;

    for(i = 0; i < N; i++)
        M[i][0] = i;

    for(j = 1; 1 << j <= N; j++)
        for(i = 0; i + (1 << j) - 1 < N; i++)
            if(A[ M[i][j - 1] ] < A[ M[i + (1 << (j - 1))][j - 1] ])
                M[i][j] = M[i][j - 1];
            else
                M[i][j] = M[i + (1 << (j - 1))][j - 1];
}

int main()
{
    int x,y,k;

    f >> N >> T;
    for(int i = 0; i < N; i++)
        f >> A[i];

    preprocesare();

    for(int i = 0; i < T; i++)
    {
        f >> x >> y;
        x--,y--;
        k = log2(y - x + 1);

        if(A[ M[x][k] ] < A[ M[y - (1 << k) + 1][k] ])
            g << A[ M[x][k] ]<< "\n";
        else
            g << A[ M[y - (1 << k) + 1][k] ]<< "\n";
    }

    /*for(int i = 0; i < N; i++)
    {
        for(int j = 0; (1 << j) <= N; j++)
            g << M[i][j] << " ";
        g << "\n";
    }*/


    return 0;
}