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Top K Frequent Elements
Asked atamazonmetagoogleapplemicrosoftbloombergoracleuber
01 · Problem
Given an integer array nums and an integer k, return the k most frequent elements. You may return the answer in any order.
It is guaranteed that the answer is unique.
02 · Examples
Example 01
Input
nums = [1,1,1,2,2,3], k = 2
Output
[1,2]
1 appears 3 times and 2 appears 2 times. The two most frequent elements are 1 and 2.
Example 02
Input
nums = [1], k = 1
Output
[1]
There is only one element, so it is the most frequent.
Example 03
Input
nums = [4,4,4,1,1,2,2,2,3], k = 2
Output
[4,2]
4 appears 3 times and 2 appears 3 times. Both are among the top 2 most frequent.
03 · Constraints
- 011 <= nums.length <= 105
- 02-104 <= nums[i] <= 104
- 03k is in the range [1, the number of unique elements in the array]
- 04It is guaranteed that the answer is unique
04 · Optimal complexity
- Time
- O(n)
- Space
- O(n)
05 · Two ways to work on it
Practice it alone or rehearse it as an interview.
Practice Mode gives you an editor and test runs, nothing else. AI Interview Mode puts a voice interviewer on the other side, adds a clock, and ends with a scored summary of the round.