Delete Node in a BST: coding question

Problem

You get the root of a binary search tree and an integer key. The input shows the tree as a list in level order. This order lists the nodes one level at a time, from left to right. A null value marks a missing child.

In a binary search tree, the value of each node is larger than all values in its left subtree. It is smaller than all values in its right subtree. The subtree of a node is that node and all nodes below it.

Delete the node whose value is key, if that node exists. The nodes that remain must also form a binary search tree. Return the root of the new tree.

Many trees can be correct. The checker accepts any binary search tree that has the correct set of values.

Example 1

Input:: root = [8,3,12,1,5,10,14], key = 3
Output:: [8,5,12,1,null,10,14]
Explanation:: Node 3 has two children. This answer puts 5, the smallest value in the right subtree of node 3, in its place.

Example 2

Input:: root = [8,3,12,1,5,10,14], key = 9
Output:: [8,3,12,1,5,10,14]
Explanation:: No node has the value 9, so the tree does not change.

Example 3

Input:: root = [6,null,9], key = 6
Output:: [9]
Explanation:: The root has only one child, so that child becomes the new root.

Constraints

0 <= number of nodes <= 10^4
-10^5 <= Node.val <= 10^5
All node values are unique.
root is a valid binary search tree.
-10^5 <= key <= 10^5

Follow-up

Delete the node in O(h) time, where h is the height of the tree.

SysRound wrote this statement. A reference solution checks every example.

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Leetcode 450. Delete Node in a BST
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Leetcode 450. Delete Node in a BST
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Problem

Delete the node whose value is key, if that node exists. The nodes that remain must also form a binary search tree. Return the root of the new tree.

Many trees can be correct. The checker accepts any binary search tree that has the correct set of values.

Example 1

Input:: root = [8,3,12,1,5,10,14], key = 3
Output:: [8,5,12,1,null,10,14]
Explanation:: Node 3 has two children. This answer puts 5, the smallest value in the right subtree of node 3, in its place.

Example 2

Input:: root = [8,3,12,1,5,10,14], key = 9
Output:: [8,3,12,1,5,10,14]
Explanation:: No node has the value 9, so the tree does not change.

Example 3

Input:: root = [6,null,9], key = 6
Output:: [9]
Explanation:: The root has only one child, so that child becomes the new root.

Constraints

0 <= number of nodes <= 10^4
-10^5 <= Node.val <= 10^5
All node values are unique.
root is a valid binary search tree.
-10^5 <= key <= 10^5

Follow-up

Delete the node in O(h) time, where h is the height of the tree.

SysRound wrote this statement. A reference solution checks every example.

Delete Node in a BST

Problem

Example 1

Example 2

Example 3

Constraints

Follow-up

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Delete Node in a BST

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