Add kotlin code for the chapter of tree (#1172)

* modified array.kt. * feat(kotlin): add kotlin code for the chapter of stack and queue. * modified array.kt * modified comments. * feat(kotlin): add kotlin code for the chapter of tree. * feat(kotlin): add kotlin code for the chapter of tree.
2026-07-14 16:16:06 +00:00 · 2024-03-25 16:22:17 +08:00
parent 202450420d
commit 5e77a64341
6 changed files with 613 additions and 0 deletions
@@ -0,0 +1,64 @@
+/**
+ * File: binary_tree_dfs.kt
+ * Created Time: 2024-01-25
+ * Author: curtishd (1023632660@qq.com)
+ */
+
+package chapter_tree
+
+import utils.TreeNode
+import utils.printTree
+
+// 初始化列表，用于存储遍历序列
+var list = ArrayList<Int>()
+
+/* 前序遍历 */
+fun preOrder(root: TreeNode?) {
+    if (root == null) return
+    // 访问优先级：根节点 -> 左子树 -> 右子树
+    list.add(root.value)
+    preOrder(root.left)
+    preOrder(root.right)
+}
+
+/* 中序遍历 */
+fun inOrder(root: TreeNode?) {
+    if (root == null) return
+    // 访问优先级：左子树 -> 根节点 -> 右子树
+    inOrder(root.left)
+    list.add(root.value)
+    inOrder(root.right)
+}
+
+/* 后序遍历 */
+fun postOrder(root: TreeNode?) {
+    if (root == null) return
+    // 访问优先级：左子树 -> 右子树 -> 根节点
+    postOrder(root.left)
+    postOrder(root.right)
+    list.add(root.value)
+}
+
+/* Driver Code */
+fun main() {
+    /* 初始化二叉树 */
+    // 这里借助了一个从数组直接生成二叉树的函数
+    val root = TreeNode.listToTree(mutableListOf(1, 2, 3, 4, 5, 6, 7))
+    println("\n初始化二叉树\n")
+    printTree(root)
+
+    /* 前序遍历 */
+    list.clear()
+    preOrder(root)
+    println("\n前序遍历的节点打印序列 = $list")
+
+    /* 中序遍历 */
+    list.clear()
+    inOrder(root)
+    println("\n中序遍历的节点打印序列 = $list")
+
+    /* 后序遍历 */
+    list.clear()
+    postOrder(root)
+    println("\n后序遍历的节点打印序列 = $list")
+}