二叉树的镜像 java

/**
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){
            return;
        }

        TreeNode temp=null;
        temp=root.left;
        root.left=root.right;
        root.right=temp;

        Mirror(root.left);
        Mirror(root.right);
    }
}