Leetcode 136. Single Number

Problem

Given a non-empty array of integers nums, every element appears twice except for one. Find that single one.

You must implement a solution with a linear runtime complexity and use only constant extra space.

Algorithm

XOR. (Sort the array is more faster?)

Code

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