剑指offer-二叉树的镜像

/**
public class TreeNode {
    int val = 0;
    TreeNode left = null;
    TreeNode right = null;

    public TreeNode(int val) {
        this.val = val;

    }

}
*/
public class Solution {
    public void Mirror(TreeNode root) {
        if(root==null)
            return ;
        
        if(root.left!=null && root.right!=null)
        {
            TreeNode p = root.left;
            root.left = root.right;
            root.right = p;
            Mirror(root.left);
            Mirror(root.right);
        }
        else if(root.left!=null && root.right==null)
        {
            root.right = root.left;
            root.left = null;
            Mirror(root.right);
        }
        else if(root.left==null && root.right!=null)
        {
            root.left = root.right;
            root.right = null;
            Mirror(root.left);
        }
        
        
    }
}