Cod sursa(job #2731087)

Utilizator bostanlucastefanBostan Luca-Stefan bostanlucastefan Data 27 martie 2021 11:55:28
Problema Range minimum query Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 0.7 kb
#include <fstream>

using namespace std;

const int N=1e5+2;

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

int n,q,st,dr,i,j;
int RMQ[20][N],p2[N];

void precalc()
{
    p2[1]=0;
    for(i=1; i<N; i++)
        p2[i]=p2[i/2]+1;

    for(i=1; i<=p2[n]; i++)
        for(j=1; j<=n-(1<<i)+1; j++)
            RMQ[i][j]=min(RMQ[i-1][j],RMQ[i-1][j+(1<<(i-1))]);
}

int query(int st,int dr)
{
    int k=p2[dr-st+1]-1;
    return min(RMQ[k][st],RMQ[k][dr-(1<<k)+1]);
}

int main()
{
    fin>>n>>q;
    for(i=1; i<=n; i++)
        fin>>RMQ[0][i];

    precalc();

    for(i=1; i<=q; i++)
    {
        fin>>st>>dr;
        fout<<query(st,dr)<<'\n';
    }
    return 0;
}