0169. Majority Element.md

题目

Given an array of size n, find the majority element. The majority element is the element that appears more than ⌊ n/2 ⌋ times.

You may assume that the array is non-empty and the majority element always exist in the array.

Example 1:

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

Example 2:

Input: [2,2,1,1,1,2,2]
Output: 2

我的思路

这题要求寻找一个数组中出现次数最多的元素，并且该元素的出现次数一定大于 ⌊ n/2 ⌋ 次。因此建立一个字典，储存每个元素出现的次数即可，若次数大于 ⌊ n/2 ⌋ ，就输出该元素。

class Solution:
    def majorityElement(self, nums: List[int]) -> int:
        dic = {}
        l = len(nums)
        for i in range(l):
            if nums[i] not in dic.keys():
                dic[nums[i]] = 1
            else:
                dic[nums[i]] += 1
            if dic[nums[i]] >= (l+1)//2:
                return nums[i]