Cod sursa(job #2836263)

Utilizator Abramiuc_AndreiAbramiuc Andrei Abramiuc_Andrei Data 19 ianuarie 2022 23:40:42
Problema Range minimum query Scor 60
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.09 kb
#include <bits/stdc++.h>
#define LOGN 16
using namespace std;
ifstream fin("rmq.in");
ofstream fout("rmq.out");

int n,m,v[100002];
int mat[100002][LOGN];

void preprocess_rmq(int mat[][LOGN], int n)
{
     for(int i=1;i<=n;i++)
          mat[i][0]=i;

     for(int j=1;(1<<j)<=n;j++)//pregatim intervalele cu lung 2^j
     {
          for(int i=1;i-1+(1<<j)<=n;i++)
          {
               if(v[mat[i][j-1]] < v[mat[i+(1<<(j-1))][j-1]])
                    mat[i][j]=mat[i][j-1];
               else
                    mat[i][j]=mat[i+(1<<(j-1))][j-1];
          }
     }
}

int rmq(int l,int r)
{
     int j=(r-l+1);
     j=int(log2(j));

     if(v[mat[l][j]]<=v[mat[r+1-(1<<j)][j]])
          return mat[l][j];
     else
          return mat[r+1-(1<<j)][j];
}

int main()
{
     //cout<<log2(100001);
     //cout<<'\n'<<(1<<16);
     fin>>n>>m;
     for(int i=1;i<=n;i++)
          fin>>v[i];
     preprocess_rmq(mat,n);

     for(int i=1;i<=m;i++)
     {
          int x,y;
          fin>>x>>y;
          fout<<v[rmq(x,y)]<<'\n';
     }
    return 0;
}