leetcode-面55-Ⅰ 数组中数字出现的次数

Xenonon

于 2020-04-28 16:30:09 发布

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文章标签： leetcode 算法 python hashmap 动态规划

本文链接：https://blog.youkuaiyun.com/Xenonon/article/details/105816690

本文介绍了两种解决LeetCode第55题的方法：一是使用Python字典进行快速解析；二是通过数组分组进行位运算求解。链接提供了详细解题思路和代码实现。

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方法一：字典

https://leetcode-cn.com/problems/shu-zu-zhong-shu-zi-chu-xian-de-ci-shu-lcof/solution/python3-zi-dian-qiao-jie-by-mu-ren-6/

class Solution:
    def singleNumbers(self, nums: List[int]) -> List[int]:
        cnt_dict = {}
        for num in nums:
            if cnt_dict.get(num):
                del cnt_dict[num]
            else:
                cnt_dict[num] = 1
        return list(cnt_dict.keys())

class Solution:
    def singleNumbers(self, nums: List[int]) -> List[int]:
        dic = collections.Counter(nums)
        return(list(key for key, value in dic.items() if value == 1))

方法二：分组亦或

https://leetcode-cn.com/problems/shu-zu-zhong-shu-zi-chu-xian-de-ci-shu-lcof/solution/shu-zu-zhong-shu-zi-chu-xian-de-ci-shu-by-leetcode/

class Solution:
    def singleNumbers(self, nums: List[int]) -> List[int]:
        ret = functools.reduce(lambda x,y: x^y, nums)
        div = 1
        while div & ret == 0:
            div <<= 1
        a, b = 0, 0
        for n in nums:
            if n & div:
                a ^= n
            else:
                b ^= n
        return [a, b]