Majority element

We can count all element in the array, and return the element that has the most count.

class Solution:
    def majorityElement(self, nums: List[int]) -> int:
        count = collections.defaultdict(int)
        for num in nums:
            count[num] += 1
        return max(count, key=count.get)

Time Complexity: O(n)
Space Complexity: O(n)