High Frequency Questions¶
This section will record all the popular questions and their follow ups during the interviews.
LeetCode 347. Top K Frequent Elements¶
- It seems that the initial problem is not hard, you can have 2 solutions:
- Using minHeap which is O(nlogk)
- Using BucketSort which is O(n)
- Solution with Dict + Sort
- The code below is using bucket sort, and i’m using the lambda function to simplify the code::
- class Solution(object):
- def topKFrequent(self, nums, k):
“”” :type nums: List[int] :type k: int :rtype: List[int] “”” # if we do a mergesort, the time completxisty will be O(nlogn) res = dict()
- for num in nums:
- if num in res:
- res[num] += 1
- res[num] = 1
# lambda is the most used functions during my work res_sorted = sorted(res.items(), key=lambda x: x) return [item for item in res_sorted[-1:-1 - k:-1]]
# I can’t believe i’m so fast that beats 93% of solutions!!!
- Solution with Heap
- Follow up–how do you update the K top results in real time?