数组中有一个数字出现的次数超过数组长度的一半，请找出这个数字。
LeetCode链接：https://leetcode-cn.com/problems/shu-zu-zhong-chu-xian-ci-shu-chao-guo-yi-ban-de-shu-zi-lcof/
class Solution:
def majorityElement(self, nums: List[int]) -> int:
counts = collections.Counter(nums)
return max(counts.keys(), key=counts.get)
