Delete Node In A BST is an example of tree problems. In this post we will see how we can solve in Javascript.

Problem Description

Given a root node reference of a BST and a key, delete the node with the given key in the BST. Return the root node reference (possibly updated) of the BST.

Basically, the deletion can be divided into two stages:

  • Search for a node to remove.
  • If the node is found, delete the node.

Note: Time complexity should be O(height of tree).

Example:

root = [5,3,6,2,4,null,7]

key = 3

 
      5
     / \
    3   6
   / \   \
  2   4   7
 

Given key to delete is 3. So we find the node with value 3 and delete it.

One valid answer is [5,4,6,2,null,null,7], shown in the following BST.

      5
     / \
    4   6
   /     \
  2       7
 

Another valid answer is [5,2,6,null,4,null,7].

      5
     / \
    2   6
     \   \
      4   7

Implementation: Please check the main.js snippet for the solution.  If you have different approach in mind or have any suggestion for this implementation feel free to share in the comment below. Thanks!