human
I found an interesting problem on https://leetcode.com/problems/single-number/:
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

I tried it in Python, but could not do it. Can you solve it?

 ... Can you provide a Python program to find that single one?
assistant
#Here is Python program to find that single one.

class Solution:
     def singleNumber(self, nums):
         """
         :type nums: List[int]
         :rtype: int
         """
         
         return(sum(set(nums))*2-sum(nums))