June Leetcoding Challenge(6.22)

LeetCode六月挑战（6.22 ）Single Number II LeetCode 137解题方案

Given a non-empty array of integers, every element appears three times except for one, which appears exactly once. Find that single one.

Note:

Your algorithm should have a linear runtime complexity. Could you implement it without using extra memory?

Example 1:

Input: [2,2,3,2]
Output: 3
Example 2:

Input: [0,1,0,1,0,1,99]
Output: 99

思路

将 数组中的数据放入Set中，然后让Set中的元素都出现三次，然后减去nums中元素的总和，这样，最后的结果为两倍数组中只出现一次的元素，最后返回1/2的结果即可。

代码

class Solution:
    def singleNumber(self, nums: List[int]) -> int:
        return (3*sum(set(nums))-sum(nums))//2