mirror of
https://github.com/krahets/hello-algo.git
synced 2024-12-26 15:16:29 +08:00
70 lines
1.7 KiB
Swift
70 lines
1.7 KiB
Swift
/**
|
||
* File: binary_tree_dfs.swift
|
||
* Created Time: 2023-01-18
|
||
* Author: nuomi1 (nuomi1@qq.com)
|
||
*/
|
||
|
||
import utils
|
||
|
||
// 初始化列表，用于存储遍历序列
|
||
var list: [Int] = []
|
||
|
||
/* 前序遍历 */
|
||
func preOrder(root: TreeNode?) {
|
||
guard let root = root else {
|
||
return
|
||
}
|
||
// 访问优先级：根结点 -> 左子树 -> 右子树
|
||
list.append(root.val)
|
||
preOrder(root: root.left)
|
||
preOrder(root: root.right)
|
||
}
|
||
|
||
/* 中序遍历 */
|
||
func inOrder(root: TreeNode?) {
|
||
guard let root = root else {
|
||
return
|
||
}
|
||
// 访问优先级：左子树 -> 根结点 -> 右子树
|
||
inOrder(root: root.left)
|
||
list.append(root.val)
|
||
inOrder(root: root.right)
|
||
}
|
||
|
||
/* 后序遍历 */
|
||
func postOrder(root: TreeNode?) {
|
||
guard let root = root else {
|
||
return
|
||
}
|
||
// 访问优先级：左子树 -> 右子树 -> 根结点
|
||
postOrder(root: root.left)
|
||
postOrder(root: root.right)
|
||
list.append(root.val)
|
||
}
|
||
|
||
@main
|
||
enum BinaryTreeDFS {
|
||
/* Driver Code */
|
||
static func 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
|
||
let root = TreeNode.listToTree(list: [1, 2, 3, 4, 5, 6, 7])!
|
||
print("\n初始化二叉树\n")
|
||
PrintUtil.printTree(root: root)
|
||
|
||
/* 前序遍历 */
|
||
list.removeAll()
|
||
preOrder(root: root)
|
||
print("\n前序遍历的结点打印序列 = \(list)")
|
||
|
||
/* 中序遍历 */
|
||
list.removeAll()
|
||
inOrder(root: root)
|
||
print("\n中序遍历的结点打印序列 = \(list)")
|
||
|
||
/* 后序遍历 */
|
||
list.removeAll()
|
||
postOrder(root: root)
|
||
print("\n后序遍历的结点打印序列 = \(list)")
|
||
}
|
||
}
|