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Commit e9cdb3e

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Merge pull request youngyangyang04#1369 from wzqwtt/tree06
添加(0226.翻转二叉树、0101.对称二叉树)Scala版本
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‎problems/0101.对称二叉树.md

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@@ -725,5 +725,25 @@ func isSymmetric3(_ root: TreeNode?) -> Bool {
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}
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```
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## Scala
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递归:
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```scala
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object Solution {
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def isSymmetric(root: TreeNode): Boolean = {
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if (root == null) return true // 如果等于空直接返回true
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def compare(left: TreeNode, right: TreeNode): Boolean = {
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if (left == null && right == null) return true // 如果左右都为空,则为true
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if (left == null && right != null) return false // 如果左空右不空,不对称,返回false
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if (left != null && right == null) return false // 如果左不空右空,不对称,返回false
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// 如果左右的值相等,并且往下递归
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left.value == right.value && compare(left.left, right.right) && compare(left.right, right.left)
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}
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// 分别比较左子树和右子树
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compare(root.left, root.right)
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}
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}
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```
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-----------------------
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<div align="center"><img src=https://code-thinking.cdn.bcebos.com/pics/01二维码一.jpg width=500> </img></div>

‎problems/0226.翻转二叉树.md

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@@ -818,5 +818,53 @@ func invertTree(_ root: TreeNode?) -> TreeNode? {
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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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def invertTree(root: TreeNode): TreeNode = {
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if (root == null) return root
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// 递归
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def process(node: TreeNode): Unit = {
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if (node == null) return
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// 翻转节点
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val curNode = node.left
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node.left = node.right
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node.right = curNode
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process(node.left)
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process(node.right)
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}
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process(root)
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root
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}
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}
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```
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广度优先遍历(层序遍历):
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```scala
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object Solution {
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import scala.collection.mutable
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def invertTree(root: TreeNode): TreeNode = {
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if (root == null) return root
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val queue = mutable.Queue[TreeNode]()
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queue.enqueue(root)
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while (!queue.isEmpty) {
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val len = queue.size
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for (i <- 0 until len) {
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var curNode = queue.dequeue()
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if (curNode.left != null) queue.enqueue(curNode.left)
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if (curNode.right != null) queue.enqueue(curNode.right)
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// 翻转
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var tmpNode = curNode.left
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curNode.left = curNode.right
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curNode.right = tmpNode
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}
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}
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root
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}
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}
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```
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<div align="center"><img src=https://code-thinking.cdn.bcebos.com/pics/01二维码一.jpg width=500> </img></div>

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