136singlenumber.py

"""
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
XOR异或运算求单身狗
"""


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


if __name__ == '__main__':
    s = Solution()
    nums = [17, 12, 5, -6, 12, 4, 17, -5, 2, -3, 2, 4, 5, 16, -3, -4, 15, 15, -4, -5, -6]
    a = s.singleNumber(nums)
    print(a)