Create is_power_of_four.py

Author: MeloveGupta

maths/is_power_of_four.py

@@ -0,0 +1,37 @@
+"""
+Check if an integer is a power of four.
+
+Time Complexity: O(log₄ n)
+Space Complexity: O(1)
+"""
+
+def is_power_of_four(n: int) -> bool:
+    """Return True if n is a power of four (n > 0).
+
+    >>> is_power_of_four(1)
+    True
+    >>> is_power_of_four(4)
+    True
+    >>> is_power_of_four(16)
+    True
+    >>> is_power_of_four(64)
+    True
+    >>> is_power_of_four(8)
+    False
+    >>> is_power_of_four(0)
+    False
+    >>> is_power_of_four(-4)
+    False
+    """
+    if not isinstance(n, int):
+        raise TypeError("n must be an integer")
+    if n <= 0:
+        return False
+    while n % 4 == 0:
+        n //= 4
+    return n == 1
+
+
+if __name__ == "__main__":
+    import doctest
+    doctest.testmod()