text: # -*- coding: utf-8 -*-
  """
  Created on Mon Dec 14 13:29:10 2020
  
  @author: Ham
  """
  
  def locate(ar, target):
      lft = 0
      rgt = len(ar) - 1
      while lft <= rgt:
          mid = (lft + rgt) // 2
          if ar[mid] == target:
              return mid
          if target < ar[mid]:
              rgt = mid - 1
          else:
              lft = mid + 1
      return -1
  
      #for i,e in enumerate(ar):
      #    if e == target:
      #        return i
      return -1
  
  ar = range(11, 34)
  print('locate([],', 20, 'found at', locate(ar, 20))
  print('locate([],', 10, 'found at', locate(ar, 10))
  print('locate([],', 50, 'found at', locate(ar, 50))
  print('locate([],', 11, 'found at', locate(ar, 11))
  print('locate([],', 33, 'found at', locate(ar, 33))
  print('locate([],', 21, 'found at', locate(ar, 21))
  print('locate([],', 22, 'found at', locate(ar, 22))
  print('locate([],', 23, 'found at', locate(ar, 23))
  print('locate([],', 24, 'found at', locate(ar, 24))
  
  