heaps · Problem 2 of 2

Top K Frequent Elements

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Given an integer array nums and an integer k, return the k most frequent elements. Return the result sorted in descending order of frequency (or ascending value if tied).

topKFrequent([1, 1, 1, 2, 2, 3], 2) -> [1, 2]
topKFrequent([1], 1)                -> [1]
topKFrequent([4, 1, -1, 2, -1, 2, 3], 2) -> [-1, 2]

Your solution

Runs your code and animates it without grading anything. Change the input to see what it does on a case the tests do not cover.

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Tests

4 cases, 1 hidden
calltypeexpectedresult
topKFrequent([1,1,1,2,2,3], 2)top 2 frequent[1,2]—
topKFrequent([1], 1)single element[1]—
topKFrequent([4,1,-1,2,-1,2,3], 2)negative numbers tied[-1,2]—
withheldhiddenwithheld—

Hidden cases run too — their inputs aren't listed here, so aim for a general solution rather than one fitted to the cases above.

Complexity

target time
O(n)
target space
O(n)

Using bucket sort achieves O(n) linear time complexity; min-heap approach achieves O(n log k).

Hints

Stuck? Hints open one at a time, each giving a little more away.

3 hints left