Cod sursa(job #1161144)

Utilizator misu007Pogonaru Mihai misu007 Data 31 martie 2014 01:59:59
Problema Range minimum query Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 0.88 kb
#include <cstdio>
#include <algorithm>
using namespace std;

const int dim=100001;

int n,m,a[dim],lg[dim],rmq[dim][18]; //2^18>dim

void read()
{
    freopen("rmq.in","r",stdin);
    scanf("%d%d",&n,&m);
    for(int i=1;i<=n;++i) scanf("%d",&a[i]);
}

void rmqf()
{
    int i,k;
    for(i=2;i<=n;++i)
    {
        lg[i]=lg[i>>1]+1;
    }
    for(i=1;i<=n;++i)
    {
        rmq[i][0]=a[i];
    }
    for(k=1;(1<<k)<=n;++k)
    {
        for(i=1;i<=n-(1<<k)+1;++i)
        {
            rmq[i][k]=min(rmq[i][k-1],rmq[i+(1<<(k-1))][k-1]);
        }
    }
}

int main()
{
    read();
    rmqf();
    freopen("rmq.out","w",stdout);
    int x,y,diff,l,sh;
    while(m)
    {
        --m;
        scanf("%d%d",&x,&y);
        diff=y-x+1;
        l=lg[diff];
        sh=diff-(1<<l);
        printf("%d\n",min(rmq[x][l],rmq[x+sh][l]));
    }
    return 0;
}