JavaScript Interview Questions: Top K Frequent Elements

Problem Statment:

Given an integer array nums and an integer k, return the k most frequent elements. You may return the answer in any order.

Example 1:

Input: nums = [1,1,1,2,2,3], k = 2
Output: [1,2]

Example 2:

Input: nums = [1], k = 1
Output: [1]

Constraints:

• 1 <= nums.length <= 105
• k is in the range [1, the number of unique elements in the array].
• It is guaranteed that the answer is unique.

Approaches

Approach 1: Simple Approach

1. Build a frequency Map.
2. sort the map in order of frequency.

Solution:

Complexity:

1. Building Map O(n)
2. Sorting: O(nlogn)

Total O(n) + O(nlogn) == O(nlogn)

Try on Leet Code

Problem: https://leetcode.com/problems/top-k-frequent-elements/

My Score:

347. Top K Frequent Elements