You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
38 lines
938 B
38 lines
938 B
/**
|
|
* File: top_k.kt
|
|
* Created Time: 2024-01-25
|
|
* Author: curtishd (1023632660@qq.com)
|
|
*/
|
|
|
|
package chapter_heap
|
|
|
|
import utils.printHeap
|
|
import java.util.*
|
|
|
|
/* 基於堆積查詢陣列中最大的 k 個元素 */
|
|
fun topKHeap(nums: IntArray, k: Int): Queue<Int> {
|
|
// 初始化小頂堆積
|
|
val heap = PriorityQueue<Int>()
|
|
// 將陣列的前 k 個元素入堆積
|
|
for (i in 0..<k) {
|
|
heap.offer(nums[i])
|
|
}
|
|
// 從第 k+1 個元素開始，保持堆積的長度為 k
|
|
for (i in k..<nums.size) {
|
|
// 若當前元素大於堆積頂元素，則將堆積頂元素出堆積、當前元素入堆積
|
|
if (nums[i] > heap.peek()) {
|
|
heap.poll()
|
|
heap.offer(nums[i])
|
|
}
|
|
}
|
|
return heap
|
|
}
|
|
|
|
/* Driver Code */
|
|
fun main() {
|
|
val nums = intArrayOf(1, 7, 6, 3, 2)
|
|
val k = 3
|
|
val res = topKHeap(nums, k)
|
|
println("最大的 $k 個元素為")
|
|
printHeap(res)
|
|
} |