题解 | #二叉树的镜像#

public class Solution {
    /**
     * 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
     *
     * 
     * @param pRoot TreeNode类 
     * @return TreeNode类
     */
    public TreeNode Mirror (TreeNode pRoot) {
          if(pRoot == null) return pRoot;
            TreeNode l =Mirror(pRoot.left);
            TreeNode r = Mirror(pRoot.right);           
            swap(pRoot);
            return  pRoot;     
    }

    public void swap(TreeNode root){
        TreeNode  t = root.left;
        root.left = root.right;
        root.right = t;
    }
}