LEETCODE 136.Singel Number

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?

大意：

找出数组中只出现一次的元素，其余的都是出现两次

注意：

你的算法需要有一个线性的复杂度。即o(n)。最好不要使用额外的memory来实现

思路： 1 ^ 1 ^ 2 ^ 2 ^ 3 = 3

class Solution(object):    def singleNumber(self, nums):        """        :type nums: List[int]        :rtype: int        """        result = nums[0]        for i in xrange(1, len(nums)):            result = result ^ nums[i]        return result