608. Tree Node

Given a table tree, id is identifier of the tree node and p_id is its parent node's id.

+----+------+
| id | p_id |
+----+------+
| 1  | null |
| 2  | 1    |
| 3  | 1    |
| 4  | 2    |
| 5  | 2    |
+----+------+

Each node in the tree can be one of three types:

• Leaf: if the node is a leaf node.
• Root: if the node is the root of the tree.
• Inner: If the node is neither a leaf node nor a root node.

 

Write a query to print the node id and the type of the node. Sort your output by the node id. The result for the above sample is:

 

+----+------+
| id | Type |
+----+------+
| 1  | Root |
| 2  | Inner|
| 3  | Leaf |
| 4  | Leaf |
| 5  | Leaf |
+----+------+

 

Explanation

 

• Node '1' is root node, because its parent node is NULL and it has child node '2' and '3'.
• Node '2' is inner node, because it has parent node '1' and child node '4' and '5'.
• Node '3', '4' and '5' is Leaf node, because they have parent node and they don't have child node.


• And here is the image of the sample tree as below:

   

  			  1
  			/   \
                        2       3
                      /   \
                    4       5
  

  Note

  If there is only one node on the tree, you only need to output its root attributes.