镜像二叉树

解析:

public void Mirror(TreeNode root) {
 	if (root == null)
 	 return; 
    swap(root);
    Mirror(root.left);
    Mirror(root.right); 
  }
 private void swap(TreeNode root) { 
    TreeNode t = root.left; 
    root.left = root.right; 
    root.right = t; 
  }