binary_swap_bits.py

"""
Swaps two bits at given positions in an integer using bitwise operators.
Wikipedia explanation: https://en.wikipedia.org/wiki/Bit_manipulation
"""


def swap_bits(number: int, i: int, j: int) -> int:
    """
    Swaps the bits at positions i and j (0-indexed from the right).

    >>> swap_bits(28, 0, 2)  # 11100 → swap rightmost bits 0 and 2
    25
    >>> swap_bits(15, 1, 2)  # 1111 → swap bits 1 and 2
    15
    >>> swap_bits(10, 0, 3)  # 1010 → swap bits 0 and 3
    3
    >>> swap_bits(10.5, 0, 3)
    Traceback (most recent call last):
        ...
    TypeError: All arguments MUST be integers!
    >>> swap_bits(-5, 1, 3)
    Traceback (most recent call last):
        ...
    ValueError: The number MUST be non-negative!
    >>> swap_bits(10, -1, 2)
    Traceback (most recent call last):
        ...
    ValueError: Bit positions MUST be non-negative!
    """

    if not all(isinstance(x, int) for x in (number, i, j)):
        raise TypeError("All arguments MUST be integers!")

    if number < 0:
        raise ValueError("The number MUST be non-negative!")

    if i < 0 or j < 0:
        raise ValueError("Bit positions MUST be non-negative!")

    # Extract the bits at positions i and j
    bit_i = (number >> i) & 1
    bit_j = (number >> j) & 1

    # Only swap if the bits are different
    if bit_i != bit_j:
        # XOR with a mask that has 1s at i and j
        number ^= (1 << i) | (1 << j)

    return number


if _name_ == "_main_":
    import doctest

    doctest.testmod()