Cod sursa(job #1379513)

Utilizator ArmandNMArmand Nicolicioiu ArmandNM Data 6 martie 2015 18:13:23
Problema Range minimum query Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.14 kb
#include <fstream>
#include <algorithm>

const int NMAX = 100005;

using namespace std;

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

int N,M,x,y,lg;
int v[NMAX];
int rmq[21][NMAX],Log[NMAX];

int minim(int a, int b)
{
    if (a < b)
        return a;
    return b;
}

int main()
{
    f >> N >> M;

    for (int i = 1; i <= N; ++i)
    {
        f >> v[i];
    }

    Log[1] = 0;
    for (int i = 2; i <= N; ++i)  //precalculare Logaritmi
    {
        Log[i]=Log[i/2]+1;
    }

    for (int i = 1; i <= N; ++i)
    {
        rmq[0][i] = i;
    }

    for (int i = 1; i <= Log[N]; ++i)
    {
        for (int j = 1; j <= N-(1<<i)+1; ++j)
        {
            if (v[ rmq[i-1][j] ] < v[ rmq[i-1][j+(1<<(i-1))] ])
            {
                rmq[i][j] = rmq[i-1][j];
            }
            else rmq[i][j] = rmq[i-1][j+(1<<(i-1))];
        }
    }

    for (int i = 1; i <= M; ++i)
    {
        f >> x >> y;
        lg = Log[y-x+1];

        int r1 = rmq[lg][x];
        int r2 = rmq[lg][y-(1<<lg)+1];

        g << minim(v[r1],v[r2]) << '\n';
    }

    f.close();
    g.close();

    return 0;
}