:orphan:

Top K Frequent Elements
=======================

.. highlight:: none

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

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:**

.. container:: example-block

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

   **Output:** [1,2]

**Example 2:**

.. container:: example-block

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

   **Output:** [1]

**Example 3:**

.. container:: example-block

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

   **Output:** [1,2]

 

**Constraints:**

- ``1 <= nums.length <= 10``\ :sup:```5```
- ``-10``\ :sup:```4```\ ``<= nums[i] <= 10``\ :sup:```4```
- ``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.

.. highlight:: python

Pattern
-------
Array, Hash Table, Divide and Conquer, Sorting, Heap (Priority Queue)

Approaches
----------

.. tab-set::

    .. tab-item:: Sorting

        **Code**

        .. literalinclude:: ../problems/medium/top-k-frequent-elements/top_k_frequent_elements__sorting.py
            :language: python
            :lines: 10-

        **Test**

        >>> from top_k_frequent_elements__sorting import topKFrequent
        >>> sorted(topKFrequent([1, 1, 1, 2, 2, 3], 2))
        [1, 2]
        >>> topKFrequent([1], 1)
        [1]

        .. autofunction:: top_k_frequent_elements__sorting.topKFrequent