260 Single Number III.py

"""
Given an array of numbers nums, in which exactly two elements appear only once and all the other elements appear exactly
twice. Find the two elements that appear only once.

For example:

Given nums = [1, 2, 1, 3, 2, 5], return [3, 5].

Note:
The order of the result is not important. So in the above example, [5, 3] is also correct.
Your algorithm should run in linear runtime complexity. Could you implement it using only constant space complexity?
Author: Rajeev Ranjan

"""


class Solution:
    def singleNumber(self, nums):
        """
        Constant space
        :type nums: list[int]
        :rtype: list[int]
        """
        bits = 0
        for elt in nums:
            bits ^= elt

        rightmost_bit_set = bits & -bits
        a = 0
        b = 0
        for elt in nums:
            if elt & rightmost_bit_set:
                a ^= elt
            else:
                b ^= elt

        return a, b