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66 lines
1.5 KiB
66 lines
1.5 KiB
/**
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* File: heap.kt
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* Created Time: 2024-01-25
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* Author: curtishd (1023632660@qq.com)
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*/
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package chapter_heap
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import utils.printHeap
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import java.util.*
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fun testPush(heap: Queue<Int>, value: Int) {
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heap.offer(value) // 元素入堆
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print("\n元素 $value 入堆后\n")
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printHeap(heap)
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}
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fun testPop(heap: Queue<Int>) {
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val value = heap.poll() // 堆顶元素出堆
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print("\n堆顶元素 $value 出堆后\n")
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printHeap(heap)
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}
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/* Driver Code */
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fun main() {
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/* 初始化堆 */
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// 初始化小顶堆
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val minHeap: PriorityQueue<Int>
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// 初始化大顶堆（使用 lambda 表达式修改 Comparator 即可）
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val maxHeap = PriorityQueue { a: Int, b: Int -> b - a }
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println("\n以下测试样例为大顶堆")
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/* 元素入堆 */
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testPush(maxHeap, 1)
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testPush(maxHeap, 3)
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testPush(maxHeap, 2)
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testPush(maxHeap, 5)
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testPush(maxHeap, 4)
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/* 获取堆顶元素 */
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val peek = maxHeap.peek()
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print("\n堆顶元素为 $peek\n")
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/* 堆顶元素出堆 */
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testPop(maxHeap)
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testPop(maxHeap)
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testPop(maxHeap)
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testPop(maxHeap)
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testPop(maxHeap)
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/* 获取堆大小 */
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val size = maxHeap.size
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print("\n堆元素数量为 $size\n")
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/* 判断堆是否为空 */
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val isEmpty = maxHeap.isEmpty()
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print("\n堆是否为空 $isEmpty\n")
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/* 输入列表并建堆 */
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// 时间复杂度为 O(n) ，而非 O(nlogn)
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minHeap = PriorityQueue(mutableListOf<Int?>(1, 3, 2, 5, 4))
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println("\n输入列表并建立小顶堆后")
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printHeap(minHeap)
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} |