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update 0226.翻转二叉树: 优化代码风格
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@ -104,7 +104,7 @@ public:
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### 深度优先遍历
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[二叉树:听说递归能做的,栈也能做!](https://programmercarl.com/二叉树的迭代遍历.html)中给出了前中后序迭代方式的写法,所以本地可以很轻松的切出如下迭代法的代码:
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[二叉树:听说递归能做的,栈也能做!](https://programmercarl.com/二叉树的迭代遍历.html)中给出了前中后序迭代方式的写法,所以本题可以很轻松的写出如下迭代法的代码:
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C++代码迭代法(前序遍历)
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@ -126,7 +126,7 @@ public:
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}
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};
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```
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如果这个代码看不懂的话可以在回顾一下[二叉树:听说递归能做的,栈也能做!](https://programmercarl.com/二叉树的迭代遍历.html)。
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如果这个代码看不懂的话可以再回顾一下[二叉树:听说递归能做的,栈也能做!](https://programmercarl.com/二叉树的迭代遍历.html)。
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我们在[二叉树:前中后序迭代方式的统一写法](https://programmercarl.com/二叉树的统一迭代法.html)中介绍了统一的写法,所以,本题也只需将文中的代码少做修改便可。
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@ -257,8 +257,7 @@ public:
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## 其他语言版本
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### Java
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Java
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```Java
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//DFS递归
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class Solution {
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@ -294,8 +293,8 @@ class Solution {
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while (size-- > 0) {
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TreeNode node = deque.poll();
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swap(node);
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if (node.left != null) {deque.offer(node.left);}
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if (node.right != null) {deque.offer(node.right);}
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if (node.left != null) deque.offer(node.left);
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if (node.right != null) deque.offer(node.right);
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}
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}
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return root;
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@ -309,7 +308,7 @@ class Solution {
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}
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```
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### Python
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Python
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递归法:前序遍历:
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```python
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@ -361,16 +360,15 @@ class Solution:
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return root
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```
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### Go
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Go
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递归版本的前序遍历
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```Go
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func invertTree(root *TreeNode) *TreeNode {
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if root ==nil{
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if root == nil {
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return nil
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}
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root.Left,root.Right=root.Right,root.Left//交换
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root.Left, root.Right = root.Right, root.Left //交换
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invertTree(root.Left)
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invertTree(root.Right)
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@ -383,12 +381,14 @@ func invertTree(root *TreeNode) *TreeNode {
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```go
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func invertTree(root *TreeNode) *TreeNode {
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if root==nil{
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if root == nil {
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return root
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}
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invertTree(root.Left)//遍历左节点
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invertTree(root.Right)//遍历右节点
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root.Left,root.Right=root.Right,root.Left//交换
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invertTree(root.Left) //遍历左节点
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invertTree(root.Right) //遍历右节点
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root.Left, root.Right = root.Right, root.Left //交换
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return root
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}
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```
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@ -397,18 +397,19 @@ func invertTree(root *TreeNode) *TreeNode {
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```go
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func invertTree(root *TreeNode) *TreeNode {
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stack:=[]*TreeNode{}
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node:=root
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for node!=nil||len(stack)>0{
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for node!=nil{
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node.Left,node.Right=node.Right,node.Left//交换
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stack=append(stack,node)
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node=node.Left
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stack := []*TreeNode{}
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node := root
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for node != nil || len(stack) > 0 {
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for node != nil {
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node.Left, node.Right = node.Right, node.Left //交换
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stack = append(stack,node)
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node = node.Left
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}
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node=stack[len(stack)-1]
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stack=stack[:len(stack)-1]
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node=node.Right
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node = stack[len(stack)-1]
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stack = stack[:len(stack)-1]
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node = node.Right
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}
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return root
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}
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```
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@ -417,25 +418,26 @@ func invertTree(root *TreeNode) *TreeNode {
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```go
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func invertTree(root *TreeNode) *TreeNode {
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stack:=[]*TreeNode{}
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node:=root
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stack := []*TreeNode{}
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node := root
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var prev *TreeNode
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for node!=nil||len(stack)>0{
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for node!=nil{
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stack=append(stack,node)
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node=node.Left
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for node != nil || len(stack) > 0 {
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for node != nil {
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stack = append(stack, node)
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node = node.Left
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}
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node=stack[len(stack)-1]
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stack=stack[:len(stack)-1]
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if node.Right==nil||node.Right==prev{
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node.Left,node.Right=node.Right,node.Left//交换
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prev=node
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node=nil
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}else {
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stack=append(stack,node)
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node=node.Right
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node = stack[len(stack)-1]
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stack = stack[:len(stack)-1]
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if node.Right == nil || node.Right == prev {
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node.Left, node.Right = node.Right, node.Left //交换
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prev = node
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node = nil
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} else {
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stack = append(stack, node)
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node = node.Right
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}
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}
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return root
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}
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```
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@ -444,21 +446,21 @@ func invertTree(root *TreeNode) *TreeNode {
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```go
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func invertTree(root *TreeNode) *TreeNode {
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if root==nil{
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if root == nil{
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return root
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}
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queue:=list.New()
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node:=root
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queue := list.New()
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node := root
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queue.PushBack(node)
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for queue.Len()>0{
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length:=queue.Len()
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for i:=0;i<length;i++{
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e:=queue.Remove(queue.Front()).(*TreeNode)
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e.Left,e.Right=e.Right,e.Left//交换
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if e.Left!=nil{
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for queue.Len() > 0 {
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length := queue.Len()
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for i := 0; i < length; i++ {
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e := queue.Remove(queue.Front()).(*TreeNode)
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e.Left, e.Right = e.Right, e.Left //交换
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if e.Left != nil {
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queue.PushBack(e.Left)
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}
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if e.Right!=nil{
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if e.Right != nil {
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queue.PushBack(e.Right)
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}
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}
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@ -467,7 +469,7 @@ func invertTree(root *TreeNode) *TreeNode {
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}
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```
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### JavaScript
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JavaScript
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使用递归版本的前序遍历
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```javascript
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@ -487,31 +489,31 @@ var invertTree = function(root) {
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```javascript
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var invertTree = function(root) {
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//我们先定义节点交换函数
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const invertNode=function(root,left,right){
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let temp=left;
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left=right;
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right=temp;
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root.left=left;
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root.right=right;
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const invertNode = function(root, left, right) {
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let temp = left;
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left = right;
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right = temp;
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root.left = left;
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root.right = right;
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}
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//使用迭代方法的前序遍历
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let stack=[];
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if(root===null){
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let stack = [];
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if(root === null) {
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return root;
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}
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stack.push(root);
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while(stack.length){
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let node=stack.pop();
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if(node!==null){
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while(stack.length) {
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let node = stack.pop();
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if(node !== null) {
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//前序遍历顺序中左右 入栈顺序是前序遍历的倒序右左中
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node.right&&stack.push(node.right);
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node.left&&stack.push(node.left);
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node.right && stack.push(node.right);
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node.left && stack.push(node.left);
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stack.push(node);
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stack.push(null);
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}else{
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node=stack.pop();
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} else {
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node = stack.pop();
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//节点处理逻辑
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invertNode(node,node.left,node.right);
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invertNode(node, node.left, node.right);
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}
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}
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return root;
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@ -521,34 +523,34 @@ var invertTree = function(root) {
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```javascript
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var invertTree = function(root) {
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//我们先定义节点交换函数
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const invertNode=function(root,left,right){
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let temp=left;
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left=right;
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right=temp;
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root.left=left;
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root.right=right;
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const invertNode = function(root, left, right) {
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let temp = left;
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left = right;
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right = temp;
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root.left = left;
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root.right = right;
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}
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//使用层序遍历
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let queue=[];
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if(root===null){
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let queue = [];
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if(root === null) {
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return root;
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}
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queue.push(root);
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while(queue.length){
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let length=queue.length;
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while(length--){
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let node=queue.shift();
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while(queue.length) {
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let length = queue.length;
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while(length--) {
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let node = queue.shift();
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//节点处理逻辑
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invertNode(node,node.left,node.right);
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node.left&&queue.push(node.left);
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node.right&&queue.push(node.right);
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invertNode(node, node.left, node.right);
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node.left && queue.push(node.left);
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node.right && queue.push(node.right);
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}
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}
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return root;
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};
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```
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### TypeScript:
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TypeScript:
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递归法:
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@ -675,7 +677,7 @@ function invertTree(root: TreeNode | null): TreeNode | null {
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};
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```
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### C
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C
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递归法
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```c
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@ -722,7 +724,7 @@ struct TreeNode* invertTree(struct TreeNode* root){
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}
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```
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### Swift:
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Swift:
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```swift
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// 前序遍历-递归
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func invertTree(_ root: TreeNode?) -> TreeNode? {
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@ -760,7 +762,7 @@ func invertTree1(_ root: TreeNode?) -> TreeNode? {
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}
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```
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### Swift
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Swift
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深度优先递归。
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@ -808,9 +810,6 @@ func invertTree(_ root: TreeNode?) -> TreeNode? {
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return root
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}
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```
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### Scala
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深度优先遍历(前序遍历):
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```scala
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object Solution {
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@ -857,7 +856,7 @@ object Solution {
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}
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```
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### rust
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rust
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```rust
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impl Solution {
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Reference in New Issue
Block a user