镜像二叉树和求二叉树最大深度（java）
* 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 null;
}
process(root);
return root;
}
public TreeNode process(TreeNode root){
if(root == null){
return null;
}
TreeNode left = process(root.left);
TreeNode right = process(root.right);
root.left = right;
root.right = left;
return root;
}
}