Cod sursa(job #1160487)

Utilizator ThomasFMI Suditu Thomas Thomas Data 30 martie 2014 16:17:02
Problema Range minimum query Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 0.89 kb
#include <fstream>
#include <algorithm>
using namespace std;

#define NMax 100005
#define LGNMax 20

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

int n,m,k=0;
int v[NMax];
int M[2*NMax][LGNMax];
int put[LGNMax];

void Preproc()
{
    int i,j,nr=1;
    while(nr<n) put[k++]=nr,nr<<=1;
    put[k]=nr;

    for(j=1;j<=k;j++) for(i=1;i<n;i++)
    {
        if(i+put[j-1]<=n) M[i][j]=min(M[i][j-1],M[i+put[j-1]][j-1]);
        else M[i][j]=M[i][j-1];
    }
}

int bs(int x)
{
    int step,j;
    for(step=1;step<=k;step<<=1);
    for(j=0;step;step>>=1)
        if(j+step<=k && put[j+step]<=x) j+=step;
    return j;
}

int main()
{
    int i,x,y,p;

    f>>n>>m;
    for(i=1;i<=n;i++)
    {
        f>>v[i];
        M[i][0]=v[i];
    }

    Preproc();

    for(i=1;i<=m;i++)
    {
        f>>x>>y;
        p=bs(y-x+1);
        g<<min(M[x][p],M[y-put[p]+1][p])<<"\n";
    }

    f.close();
    g.close();
    return 0;
}