ds-algo-study/DS-n-Algos/Trees/leetcode-450-delete-bst-node/Delete Node in a BST.md

Just experimenting with publishing a package

# Delete Node in a BST

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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:

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

**Follow up:** Can you solve it with time complexity `O(height of tree)`?

**Example 1:**

![](https://assets.leetcode.com/uploads/2020/09/04/del_node_1.jpg)

**Input:** root = \[5,3,6,2,4,null,7\], key = 3
**Output:** \[5,4,6,2,null,null,7\]
**Explanation:** 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 above BST.
Please notice that another valid answer is \[5,2,6,null,4,null,7\] and it's also accepted.
![](https://assets.leetcode.com/uploads/2020/09/04/del_node_supp.jpg)

**Example 2:**

**Input:** root = \[5,3,6,2,4,null,7\], key = 0
**Output:** \[5,3,6,2,4,null,7\]
**Explanation:** The tree does not contain a node with value = 0.

**Example 3:**

**Input:** root = \[\], key = 0
**Output:** \[\]

**Constraints:**

*   The number of nodes in the tree is in the range `[0, 104]`.
*   `-105 <= Node.val <= 105`
*   Each node has a **unique** value.
*   `root` is a valid binary search tree.
*   `-105 <= key <= 105`


[Source](https://leetcode.com/problems/delete-node-in-a-bst/)