Cod sursa(job #1967749)

Utilizator DiClauDan Claudiu DiClau Data 17 aprilie 2017 00:33:42
Problema Range minimum query Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.36 kb
#include<stdio.h>
using namespace std;
const int L = 18, N = 100005;
int putere, mat[L][N], puteri[L], log[N];
int minim (int a, int b)
{
    return a < b ? a : b;
}
void precalc (int n)
{
    int i;
    for (i = 1; i <= n; i<<=1);
    int p = 1, ct = 0;
    for (i = 1; i <= N; i++)
    {
        if ((p << 1) <= i)
        {
            p <<= 1;
            ct++;
        }
        log[i] = ct;
        puteri[ct] = p;
    }
    putere = i;

}
void buildRmq (int n)
{
    int i, j, p = 1, aux;
    for (i = 1; i <= L - 2; i++)
    {
        aux = p;
        p <<= 1;
        for (j = 1; j <= n - p + 1; j++)
            mat[i][j] = minim (mat[i - 1][j], mat[i - 1][j + aux]);
    }
}
int interogRmq (int a, int b)
{
    int p;
    int aux;
    if (a > b)
    {
        aux = a;
        a = b;
        b = aux;
    }
    p = log[b - a + 1];
    aux = puteri[p];
    return minim (mat[p][a], mat[p][b - aux + 1]);
}
int main ()
{
    FILE *in, *out;
    in = fopen ("rmq.in", "r");
    out = fopen ("rmq.out", "w");
    int n, m;
    fscanf (in, "%d%d", &n, &m);
    precalc (n);
    int i, a, b;
    for (i = 1; i <= n; i++)
        fscanf (in, "%d", &mat[0][i]);
    buildRmq(n);
    for (i = 1; i <= m; i++)
    {
        fscanf (in, "%d%d", &a, &b);
        fprintf (out, "%d\n", interogRmq(a, b));
    }
    return 0;
}