Binary search if array contains duplicates

Question

Hi,

what is the index of the search key if we search for 24 in the following array using binary search.

array = [10,20,21,24,24,24,24,24,30,40,45]
         


        

Answer 1

It works in both unique and non-unique array.

def binary_search(n,s):
  search = s
  if len(n) < 1:
    return "{} is not in array".format(search)
  if len(n) == 1 and n[0] != s:
    return "{} is not in array".format(search)
  
  mid = len(n)//2
  ele = n[mid]
  if search == ele:
    return "{} is in array".format(search)
  elif search > ele:
    return binary_search(n[mid:],search)
  else:
    return binary_search(n[:mid],search)