Skip to main content

Top K Frequent Elements

Problem statement​

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 = 2Output: [1,2]

Example 2:

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

Follow up: Your algorithm's time complexity must be better than O(n log n), where n is the array's size.

My solution​

/**
 * @param {number[]} nums
 * @param {number} k
 * @return {number[]}
 */
var topKFrequent = function(nums, k) {
    const memo = new Map();
    
    for (const num of nums) {
        memo.set(num, (memo.get(num) || 0) + 1)
    }
    
    const result = [...memo].sort((a, b) => b[1] - a[1])
    
    // console.log(result)
    
    return result.slice(0, k).map(([key]) => key)
};