hello-algo/zh-hant/codes/kotlin/chapter_tree/binary_tree_bfs.kt
Yudong Jin d484b08c15
Prepare 1.1.0 release (#1274)
* Update bucket_sort.c

* Fix the comments in quick_sort.c

* Update the announce badge

* Sync zh and zh-hant versions

* Update contributors list.

* Sync zh and zh-hant versions.

* Sync zh and zh-hant versions.

* Update the contributors list

* Update the version number
2024-04-14 20:46:20 +08:00

42 lines
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1.1 KiB
Kotlin

/**
* File: binary_tree_bfs.kt
* Created Time: 2024-01-25
* Author: curtishd (1023632660@qq.com)
*/
package chapter_tree
import utils.TreeNode
import utils.printTree
import java.util.*
/* 層序走訪 */
fun levelOrder(root: TreeNode?): MutableList<Int> {
// 初始化佇列,加入根節點
val queue = LinkedList<TreeNode?>()
queue.add(root)
// 初始化一個串列,用於儲存走訪序列
val list = mutableListOf<Int>()
while (queue.isNotEmpty()) {
val node = queue.poll() // 隊列出隊
list.add(node?._val!!) // 儲存節點值
if (node.left != null)
queue.offer(node.left) // 左子節點入列
if (node.right != null)
queue.offer(node.right) // 右子節點入列
}
return list
}
/* Driver Code */
fun main() {
/* 初始化二元樹 */
// 這裡藉助了一個從串列直接生成二元樹的函式
val root = TreeNode.listToTree(mutableListOf(1, 2, 3, 4, 5, 6, 7))
println("\n初始化二元樹\n")
printTree(root)
/* 層序走訪 */
val list = levelOrder(root)
println("\n層序走訪的節點列印序列 = $list")
}