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Top K Frequent Elements

Question​

Given an unsorted array of numbers, find the K most frequent elements in the array.

Example 1
Input: [1,1,1,2,2,3]
k = 2

Output: [1,2]

Solution​

all//Top K Frequent Elements.py


# Solution
class Solution:
    def topKFrequent(self, nums, k):
        # create a dictionary to store the frequency of each number
        freq_dict = {}
        for num in nums:
            if num in freq_dict:
                freq_dict[num] += 1
            else:
                freq_dict[num] = 1

        # create a list of tuples (number, frequency)
        freq_list = []
        for num, freq in freq_dict.items():
            freq_list.append((num, freq))

        # sort the list in descending order
        freq_list.sort(key=lambda x: x[1], reverse=True)

        # return the top k elements
        return [x[0] for x in freq_list[:k]]