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347-top_k_frequent_elements.py
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347-top_k_frequent_elements.py
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"""
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:
Input: nums = [1,1,1,2,2,3], k = 2
Output: [1,2]
Example 2:
Input: nums = [1], k = 1
Output: [1]
Constraints:
1 <= nums.length <= 10^5
-10^4 <= nums[i] <= 10^4
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.
"""
from collections import defaultdict
def topKFrequent(nums: list[int], k: int) -> list[int]:
frequencies = defaultdict(int)
for num in nums:
frequencies[num] += 1
sortedFrequencies = sorted(frequencies.items(), key=lambda x: x[1], reverse=True)
result = []
for i in range(k):
result.append(sortedFrequencies[i][0])
return result
if __name__ == '__main__':
nums = [1,1,1,2,2,3]
k = 2
print(topKFrequent(nums, k))