Single Number

Question

Given an array of integers, every element appears twice except for one. Find that single one.

Note: Your algorithm should have a linear runtime complexity. Could you implement it without using extra memory?

Tags

• Hash Table
• Bit Manipulation

Thought

Utilize the bitwise exclusive or operation to obtain the single number from the array.

Code

class Solution(object):
    def singleNumber(self, nums):
        """
        :type nums: List[int]
        :rtype: int
        """
        result = 0
        for num in nums:
            result = result ^ num
        return result