169. Majority Element

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
Solution in python:

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

Complexity analysis:

• Time complexity: O(N)
• Space complexity: O(N)