5/30/2017 - 2:42 PM

136. Single Number

  1. Single Number
class Solution(object):
    def singleNumber(self, nums):
        :type nums: List[int]
        :rtype: int
        res = 0
        for each in nums:
            res ^= each
        return res

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?