def xor_swap_characters(text_list: list[str], left: int, right: int) -> None:
"""
Swaps two characters in a list of characters in-place using the XOR swap algorithm.
This function demonstrates bitwise XOR swapping for educational purposes.
In idiomatic Python, tuple assignment (text[left], text[right] = text[right], text[left])
is strongly preferred for performance and readability.
:param text_list: Mutable list of single-character strings.
:param left: Zero-based index of the first character.
:param right: Zero-based index of the second character.
"""
length = len(text_list)
# Bounds checking and negative index protection
if length == 0 or left < 0 or left >= length or right < 0 or right >= length:
return
# XOR swap fails if left == right because (x ^ x) evaluates to 0
if left == right:
return
# Convert characters to Unicode code points, apply XOR, and map back to chars
text_list[left] = chr(ord(text_list[left]) ^ ord(text_list[right]))
text_list[right] = chr(ord(text_list[right]) ^ ord(text_list[left]))
text_list[left] = chr(ord(text_list[left]) ^ ord(text_list[right]))
def main() -> None:
original = "hello"
text_list = list(original)
print(f"Before: {''.join(text_list)}")
xor_swap_characters(text_list, 1, 4)
result = "".join(text_list)
print(f"After: {result}")
if __name__ == "__main__":
main()
'''
run:
Before: hello
After: holle
'''
