Add perfect cube binary search

maths/perfect_cube.py

@@ -11,6 +11,45 @@ def perfect_cube(n: int) -> bool:
  return (val * val * val) == n
 
 
+def perfect_cube_binary_search(n: int) -> bool:
+ """
+ Check if a number is a perfect cube or not using binary search.
+ Time complexity : O(Log(n))
+ Space complexity: O(1)
+
+ >>> perfect_cube_binary_search(27)
+ True
+ >>> perfect_cube_binary_search(64)
+ True
+ >>> perfect_cube_binary_search(4)
+ False
+ >>> perfect_cube_binary_search("a")
+ Traceback (most recent call last):
+ ...
+ TypeError: perfect_cube_binary_search() only accepts integers
+ >>> perfect_cube_binary_search(0.1)
+ Traceback (most recent call last):
+ ...
+ TypeError: perfect_cube_binary_search() only accepts integers
+ """
+ if not isinstance(n, int):
+ raise TypeError("perfect_cube_binary_search() only accepts integers")
+ if n < 0:
+ n = -n
+ left = 0
+ right = n
+ while left <= right:
+ mid = left + (right - left) // 2
+ if mid * mid * mid == n:
+ return True
+ elif mid * mid * mid < n:
+ left = mid + 1
+ else:
+ right = mid - 1
+ return False
+
+
 if __name__ == "__main__":
- print(perfect_cube(27))
- print(perfect_cube(4))
+ import doctest
+
+ doctest.testmod()