347. Top K Frequent Elements

Medium

30 Points

Array

Hash Table

Divide and Conquer

Sorting

Heap (Priority Queue)

Bucket Sort

Counting

Quickselect

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

Examples

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
-104 <= nums[i] <= 104
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.