python count built-in function example

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

Brute-force way => comparing every elements while loop. However, if we use count function we can solve this problem easily.

class Solution:

    def singleNumber(self, nums):

        """

        :type nums: List[int]

        :rtype: int

        """

        

        for i in nums:

            if nums.count(i) == 1:

                return i

Reference site : https://leetcode.com/explore/interview/card/top-interview-questions-easy/92/array/549/discuss/218445/simple-python-solution