diff --git a/bit_manipulation/find_unique_number.py b/bit_manipulation/find_unique_number.py new file mode 100644 index 000000000..77970b486 --- /dev/null +++ b/bit_manipulation/find_unique_number.py @@ -0,0 +1,37 @@ +def find_unique_number(arr: list[int]) -> int: + """ + Given a list of integers where every element appears twice except for one, + this function returns the element that appears only once using bitwise XOR. + + >>> find_unique_number([1, 1, 2, 2, 3]) + 3 + >>> find_unique_number([4, 5, 4, 6, 6]) + 5 + >>> find_unique_number([7]) + 7 + >>> find_unique_number([10, 20, 10]) + 20 + >>> find_unique_number([]) + Traceback (most recent call last): + ... + ValueError: input list must not be empty + >>> find_unique_number([1, 'a', 1]) + Traceback (most recent call last): + ... + TypeError: all elements must be integers + """ + if not arr: + raise ValueError("input list must not be empty") + if not all(isinstance(x, int) for x in arr): + raise TypeError("all elements must be integers") + + result = 0 + for num in arr: + result ^= num + return result + + +if __name__ == "__main__": + import doctest + + doctest.testmod()