11def perfect_cube (n : int ) -> bool :
22 """
33 Check if a number is a perfect cube or not.
4-
4+
55 Note: This method uses floating point arithmetic which may be
66 imprecise for very large numbers.
7-
7+
88 >>> perfect_cube(27)
99 True
1010 >>> perfect_cube(64)
@@ -30,12 +30,12 @@ def perfect_cube(n: int) -> bool:
3030 is_negative = True
3131 else :
3232 is_negative = False
33-
33+
3434 val = n ** (1 / 3 )
3535 # Round to avoid floating point precision issues
3636 rounded_val = round (val )
3737 result = rounded_val * rounded_val * rounded_val == n
38-
38+
3939 # For negative numbers, we need to check if the cube root would be negative
4040 return result and not (is_negative and rounded_val == 0 )
4141
@@ -45,7 +45,7 @@ def perfect_cube_binary_search(n: int) -> bool:
4545 Check if a number is a perfect cube or not using binary search.
4646 Time complexity : O(Log(n))
4747 Space complexity: O(1)
48-
48+
4949 >>> perfect_cube_binary_search(27)
5050 True
5151 >>> perfect_cube_binary_search(64)
@@ -93,29 +93,29 @@ def perfect_cube_binary_search(n: int) -> bool:
9393 """
9494 if not isinstance (n , int ):
9595 raise TypeError ("perfect_cube_binary_search() only accepts integers" )
96-
96+
9797 # Handle zero and negative numbers
9898 if n == 0 :
9999 return True
100100 if n < 0 :
101101 n = - n
102-
102+
103103 # Quick checks to eliminate obvious non-cubes
104104 # Check last three digits using modulo arithmetic
105105 # Only 0, 1, 8, 7, 4, 5, 6, 3, 2, 9 can be cubes mod 10
106106 # But for cubes, the pattern is more complex
107107 last_digit = n % 10
108108 if last_digit not in {0 , 1 , 8 , 7 , 4 , 5 , 6 , 3 , 2 , 9 }:
109109 return False
110-
110+
111111 # More refined check: cubes mod 7 can only be 0, 1, 6
112112 if n % 7 not in {0 , 1 , 6 }:
113113 return False
114-
114+
115115 # More refined check: cubes mod 9 can only be 0, 1, 8
116116 if n % 9 not in {0 , 1 , 8 }:
117117 return False
118-
118+
119119 # Estimate the cube root using logarithms for very large numbers
120120 # This gives us a much better initial right bound
121121 if n > 10 ** 18 :
@@ -128,7 +128,7 @@ def perfect_cube_binary_search(n: int) -> bool:
128128 else :
129129 # For smaller numbers, use the standard approach
130130 left , right = 0 , n // 2 + 1
131-
131+
132132 # Binary search
133133 while left <= right :
134134 mid = (left + right ) // 2
@@ -137,19 +137,19 @@ def perfect_cube_binary_search(n: int) -> bool:
137137 if mid > 10 ** 6 and mid * mid > n // mid :
138138 right = mid - 1
139139 continue
140-
140+
141141 cube = mid * mid * mid
142142 if cube == n :
143143 return True
144144 elif cube < n :
145145 left = mid + 1
146146 else :
147147 right = mid - 1
148-
148+
149149 return False
150150
151151
152152if __name__ == "__main__" :
153153 import doctest
154154
155- doctest .testmod ()
155+ doctest .testmod ()
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