--- title: '347. Top K Frequent Elements' description: Given an integer array nums and an integer k, return the k most frequent elements. You may return the answer in any order sidebar: label: 'Top K Frequent Elements' badge: 'Medium' --- Hash Table ::::warning Your algorithm's time complexity must be better than O(n log n), where n is the array's size. :::: ### Example 1: - Input: `nums = [1,1,1,2,2,3], k = 2` - Output: `[1,2]` ### Example 2: - Input: `nums = [1], k = 1` - Output: `[1]` ### Example 3: - Input: `nums = [1,2,1,2,1,2,3,1,3,2], k = 2` - Output: `[1,2]` ### Constraints: - `1 <= nums.length <= 10^5` - `-10^4 <= nums[i] <= 10^4` - `k` is in the range `[1, the number of unique elements in the array]`. - It is guaranteed that the answer is unique. ## Solution ```js /** * @param {number[]} nums * @param {number} k * @return {number[]} */ var topKFrequent = function (nums, k) { const freq = {}; for (let n of nums) freq[n] = (freq[n] || 0) + 1; return Object.keys(freq) .map(Number) .sort((a, b) => freq[b] - freq[a]) .slice(0, k); }; ```