Single Number in Python

Given a non-empty 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?

Example 1:

Input: [2,2,1]
Output: 1

Example 2:

Input: [4,1,2,1,2]

Output: 4

class Solution:
    def singleNumber(self, nums: List[int]) -> int:
        result = nums[0]
        for i in range(1, len(nums)):
            result = result ^ nums[i]
        return result

TIme Complexity : O(n)
Space Complexity : O(1)