Bit manipulation algorithm to check is_power_of_four

bit_manipulation/decimal_to_binary.py

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+"""
+Author :- mehul-sweeti-agrawal
+
+Task :- Given a positive decimal integer, convert it to binary
+
+    Input  - 9
+    Output - 1001
+
+"""
+
+
+def convert_to_binary(number: int) -> int:
+    """
+    Returns binary equivalent of a decimal number
+    >>> convert_to_binary(8)
+    1000
+    >>> convert_to_binary(5)
+    101
+    >>> convert_to_binary(-3)
+    Traceback (most recent call last):
+      ...
+    ValueError: number must be non-negative
+    >>> convert_to_binary(9.8)
+    Traceback (most recent call last):
+      ...
+    TypeError: unsupported operand type(s) for &: 'float' and 'int'
+    """
+
+    # For negative numbers
+    if number < 0:
+        raise ValueError("number must be non-negative")
+
+    power = 1  # helper variable
+    ans = 0  # stores binary equivalent of decimal number
+    while number:
+        if number & 1:
+            ans += power
+        power *= 10
+        number >>= 1
+    return ans
+
+
+if __name__ == "__main__":
+    import doctest
+
+    doctest.testmod()

bit_manipulation/is_power_of_four.py

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+"""
+Author :- mehul-sweeti-agrawal
+
+Task :- Given an integer N, find whether that integer is a power of 4 or not.
+
+    Input  - N
+    Output - Yes/No
+
+"""
+
+
+def is_power_of_four(N: int) -> bool:
+    """
+    Returns whether a number is a power of 4 or not
+    >>> is_power_of_four(8)
+    False
+    >>> is_power_of_four(4)
+    True
+    >>> is_power_of_four(16)
+    True
+    >>> is_power_of_four(-1)
+    Traceback (most recent call last):
+        ...
+    ValueError: number must be positive
+    >>> is_power_of_four(9.8)
+    Traceback (most recent call last):
+        ...
+    TypeError: unsupported operand type(s) for &: 'float' and 'float'
+    """
+
+    # For non-positive numbers
+    if N <= 0:
+        raise ValueError("number must be positive")
+
+    # If number is a power of 2 and ends with 4 or 6
+    if (N & (N - 1) == 0) and (N % 10 == 6 or N % 10 == 4):
+        return True
+    else:
+        return False
+
+
+if __name__ == "__main__":
+    import doctest
+
+    doctest.testmod()