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40 lines
1 KiB
Python
40 lines
1 KiB
Python
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"""
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File: top_k.py
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Created Time: 2023-06-10
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Author: krahets (krahets@163.com)
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"""
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import sys
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from pathlib import Path
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sys.path.append(str(Path(__file__).parent.parent))
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from modules import print_heap
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import heapq
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def top_k_heap(nums: list[int], k: int) -> list[int]:
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"""Using heap to find the largest k elements in an array"""
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# Initialize min-heap
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heap = []
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# Enter the first k elements of the array into the heap
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for i in range(k):
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heapq.heappush(heap, nums[i])
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# From the k+1th element, keep the heap length as k
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for i in range(k, len(nums)):
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# If the current element is larger than the heap top element, remove the heap top element and enter the current element into the heap
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if nums[i] > heap[0]:
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heapq.heappop(heap)
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heapq.heappush(heap, nums[i])
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return heap
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"""Driver Code"""
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if __name__ == "__main__":
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nums = [1, 7, 6, 3, 2]
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k = 3
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res = top_k_heap(nums, k)
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print(f"The largest {k} elements are")
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print_heap(res)
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