# ---
# title: 450. Delete Node in a BST
# id: problem450
# author: Tian Jun
# date: 2020-10-31
# difficulty: Medium
# categories: Tree
# link: <https://leetcode.com/problems/delete-node-in-a-bst/description/>
# hidden: true
# ---
# 
# 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`
# 
# 
## @lc code=start
using LeetCode

## add your code here:
## @lc code=end
