Cod sursa(job #1839485)

Utilizator jurjstyleJurj Andrei jurjstyle Data 2 ianuarie 2017 22:50:18
Problema Range minimum query Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.05 kb
#include <fstream>
#include <cmath>
#include <vector>
#include <iostream>

using namespace std;

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


int n, m;
vector <int> V;
int a[100002][18];

void preprocess ()
{
    for (int i = 1; i <= n; ++i)
        a[i][0] = i;
    for (int j = 1; pow(2,j-1) <= n; ++j)
    {
        int k = 1;
        for (int cnt = 1; cnt < j; ++cnt)
            k *= 2;
        for (int i = 1; i + k <= n; ++i)
            if ( V[a[i][j-1]] < V[a[i+k][j-1]] )
                a[i][j] = a[i][j-1];
            else
                a[i][j] = a[i+k][j-1];
    }
}


int main()
{
    f >> n >> m;
    V.resize (n + 1);
    for (int i = 1; i <= n; ++i)
        f >> V[i];
    preprocess();
    for (int i = 1; i <= m; ++i)
    {
        int x, y;
        f >> x >> y;
        int k = log2 (y - x + 1);
        int k2 = 1 ;
        for (int cnt = 1; cnt <= k ; ++cnt )
            k2 *= 2;
        g << min ( V[a[x][k]] , V[a[y-k2+1][k]] ) << "\n";
    }
    f.close();
    g.close();
    return 0;
}