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feat: add Swift codes for top_k article (#578)

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nuomi1 2023-07-06 03:16:14 +08:00 committed by GitHub
parent 55d8b710fa
commit b4de2c0d13
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2 changed files with 37 additions and 0 deletions
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2
codes/swift/Package.swift
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@ -39,6 +39,7 @@ let package = Package(
.executable(name: "avl_tree", targets: ["avl_tree"]),
// chapter_heap
.executable(name: "my_heap", targets: ["my_heap"]),
.executable(name: "top_k", targets: ["top_k"]),
// chapter_graph
.executable(name: "graph_adjacency_matrix", targets: ["graph_adjacency_matrix"]),
.executable(name: "graph_adjacency_list", targets: ["graph_adjacency_list"]),
@ -107,6 +108,7 @@ let package = Package(
.executableTarget(name: "avl_tree", dependencies: ["utils"], path: "chapter_tree", sources: ["avl_tree.swift"]),
// chapter_heap
.executableTarget(name: "my_heap", dependencies: ["utils"], path: "chapter_heap", sources: ["my_heap.swift"]),
.executableTarget(name: "top_k", dependencies: ["utils"], path: "chapter_heap", sources: ["top_k.swift"]),
// chapter_graph
.executableTarget(name: "graph_adjacency_matrix", dependencies: ["utils"], path: "chapter_graph", sources: ["graph_adjacency_matrix.swift"]),
.executableTarget(name: "graph_adjacency_list", dependencies: ["utils"], path: "chapter_graph", sources: ["graph_adjacency_list.swift"]),

35
codes/swift/chapter_heap/top_k.swift Normal file
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@ -0,0 +1,35 @@
/**
* File: top_k.swift
* Created Time: 2023-07-02
* Author: nuomi1 (nuomi1@qq.com)
*/
import utils
/* 基于堆查找数组中最大的 k 个元素 */
func topKHeap(nums: [Int], k: Int) -> [Int] {
// 将数组的前 k 个元素入堆
var heap = Array(nums.prefix(k))
// 从第 k+1 个元素开始，保持堆的长度为 k
for i in stride(from: k, to: nums.count, by: 1) {
// 若当前元素大于堆顶元素，则将堆顶元素出堆、当前元素入堆
if nums[i] > heap.first! {
heap.removeFirst()
heap.insert(nums[i], at: 0)
}
}
return heap
}
@main
enum TopK {
/* Driver Code */
static func main() {
let nums = [1, 7, 6, 3, 2]
let k = 3
let res = topKHeap(nums: nums, k: k)
print("最大的 \(k) 个元素为")
PrintUtil.printHeap(queue: res)
}
}