mirror of
https://github.com/TheAlgorithms/Python.git
synced 2024-11-24 13:31:07 +00:00
27 lines
645 B
Python
27 lines
645 B
Python
|
# A binary search implementation to test if a number is in a list of elements
|
||
|
|
|
||
|
|
|
||
|
|
def binary_search(a_list, item):
|
||
|
|
"""
|
||
|
|
>>> test_list = [0, 1, 2, 8, 13, 17, 19, 32, 42]
|
||
|
|
>>> print(binary_search(test_list, 3))
|
||
|
|
False
|
||
|
|
>>> print(binary_search(test_list, 13))
|
||
|
|
True
|
||
|
|
"""
|
||
|
|
if len(a_list) == 0:
|
||
|
|
return False
|
||
|
|
midpoint = len(a_list) // 2
|
||
|
|
if a_list[midpoint] == item:
|
||
|
|
return True
|
||
|
|
if item < a_list[midpoint]:
|
||
|
|
return binary_search(a_list[:midpoint], item)
|
||
|
|
else:
|
||
|
|
return binary_search(a_list[midpoint + 1 :], item)
|
||
|
|
|
||
|
|
|
||
|
|
if __name__ == "__main__":
|
||
|
|
import doctest
|
||
|
|
|
||
|
|
doctest.testmod()
|