Binary Tree Nodes :- HackerRank SQL Solution in MYSQL

Problem:-

You are given a table, BST, containing two columns: N and P, where N represents the value of a node in Binary Tree, and P is the parent of N.

Write a query to find the node type of Binary Tree ordered by the value of the node. Output one of the following for each node:

• Root: If node is root node.
• Leaf: If node is leaf node.
• Inner: If node is neither root nor leaf node.

Sample Input

Sample Output

1 Leaf
2 Inner
3 Leaf
5 Root
6 Leaf
8 Inner
9 Leaf

Explanation

The Binary Tree below illustrates the sample:

Solution:-

SELECT N, IF(P IS NULL,'Root',IF((SELECT COUNT(*) FROM BST WHERE P=B.N)>0,'Inner','Leaf')) FROM BST AS B ORDER BY N;