Cod sursa(job #1070745)

Utilizator VisuianMihaiMihai Visuian VisuianMihai Data 1 ianuarie 2014 21:28:04
Problema Range minimum query Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 0.94 kb
#include <fstream>
using namespace std;

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

int n, m, x, y, lg[100000], a[100000],rmq[100000][20];

int main()
{
    fin>>n>>m;
    for(int i = 0; i< n; i++)
        fin>>a[i];

//computing the logarithms
    for(int i = 2; i<= n; i++ )
        lg[i]=1+lg[i>>1];

//preprocessing the rmq
    for(int i = 0; i< n; i++ )
        rmq[i][0]=i;
    for(int j = 1; (1<<j)<=n; j++)
        for(int i = 0; i+(1<<j)-1<n; i++)
            if(a[rmq[i][j-1]]<a[rmq[i+(1<<(j-1))][j-1]])
                rmq[i][j]=rmq[i][j-1];
            else rmq[i][j]=rmq[i+(1<<(j-1))][j-1];

//queries
    for(int i = 1; i<= m; i++)
    {
        fin>>x>>y;
        if(x>y) swap(x,y);
        int l=lg[y-x+1];
        if(a[rmq[x-1][l]]<a[rmq[y-(1<<l)][l]])
            fout<<a[rmq[x-1][l]]<<'\n';
        else fout<<a[rmq[y-(1<<l)][l]]<<'\n';
    }

    fin.close();
    fout.close();
    return 0;
}