63 lines
1014 B
Markdown
63 lines
1014 B
Markdown
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---
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layout: page
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title: SQL Binary Tree Nodes
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last_solved:
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category: sql
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leetcode_url: https://www.hackerrank.com/challenges/binary-search-tree-1
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status: Attempted
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---
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Problem
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-------
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```
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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.
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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:
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Root: If node is root node.
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Leaf: If node is leaf node.
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Inner: If node is neither root nor leaf node.
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Sample Input
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Sample Output
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1 Leaf
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2 Inner
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3 Leaf
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5 Root
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6 Leaf
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8 Inner
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9 Leaf
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Explanation
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The Binary Tree below illustrates the sample:
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```
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Solution
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----------
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{% highlight sql %}
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select n,
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case
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when p is null then 'Root'
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-- case when n not in (2,6,4,15,9,13,11) then 'Leaf' else 'Inner'
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when n in (select distinct p from bst) then 'Inner'
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else 'Leaf'
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end
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end
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from bst
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order by n;
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{% endhighlight %}
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![image1]()
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