Top K Frequent Elements

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

Given an integer array nums and an integer k, return the k most frequent elements.

1import heapq
2
3def topKFrequent(nums: List[int], k: int) -> List[int]:
4    freq = {}
5    for x in nums:
6        freq[x] = freq.get(x, 0) + 1
7        
8    heap = []
9    for x, f in freq.items():
10        heapq.heappush(heap, (f, x))
11        if len(heap) > k:
12            heapq.heappop(heap)
13            
14    return [x for (_, x) in heap]

Kth Largest Element in an Array

K Closest Points to Origin

k=2

Step 1 / 3

Step 1:

Count frequencies, then keep a min-heap of size k by frequency.

Focus: select @ [0, 3, 5]

k=2