226. Invert Binary Tree

问题
Given the root of a binary tree, invert the tree, and return its root.

翻转二叉树。
交换当前节点的左右子节点。
分别递归其左右子节点。
当当前节点的两个节点均为null时返回。

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/**
* Definition for a binary tree node.
* public class TreeNode {
* int val;
* TreeNode left;
* TreeNode right;
* TreeNode() {}
* TreeNode(int val) { this.val = val; }
* TreeNode(int val, TreeNode left, TreeNode right) {
* this.val = val;
* this.left = left;
* this.right = right;
* }
* }
*/
class Solution {
public TreeNode invertTree(TreeNode root) {
if (root == null){
return root;
}
invert(root);
return root;
}

private void invert(TreeNode root){
if ( root.left == null && root.right == null){
return;
}
TreeNode temp = root.left;
root.left = root.right;
root.right = temp;
if ( root.left != null ){
invert(root.left);
}
if ( root.right != null ){
invert(root.right);
}
}
}
Author

Xander

Posted on

2022-04-13

Updated on

2022-04-13

Licensed under

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