37 lines
970 B
Swift
37 lines
970 B
Swift
/**
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* File: top_k.swift
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* Created Time: 2023-07-02
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* Author: nuomi1 (nuomi1@qq.com)
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*/
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import HeapModule
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import utils
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/* Using heap to find the largest k elements in an array */
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func topKHeap(nums: [Int], k: Int) -> [Int] {
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// Initialize a min-heap and build the top k elements
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var heap = Heap(nums.prefix(k))
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// From the k+1th element, keep the heap length as k
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for i in nums.indices.dropFirst(k) {
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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.min()! {
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_ = heap.removeMin()
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heap.insert(nums[i])
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}
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}
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return heap.unordered
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}
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@main
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enum TopK {
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/* Driver Code */
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static func main() {
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let nums = [1, 7, 6, 3, 2]
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let k = 3
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let res = topKHeap(nums: nums, k: k)
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print("The largest \(k) elements are")
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PrintUtil.printHeap(queue: res)
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}
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}
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