human
Solve in Python:
Return the root node of a binary search tree that matches the given preorder traversal.
(Recall that a binary search tree is a binary tree where for every node, any descendant of node.left has a value < node.val, and any descendant of node.right has a value > node.val.  Also recall that a preorder traversal displays the value of the node first, then traverses node.left, then traverses node.right.)
It's guaranteed that for the given test cases there is always possible to find a binary search tree with the given requirements.
Example 1:
Input: [8,5,1,7,10,12]
Output: [8,5,10,1,7,null,12]

 
Constraints:

1 <= preorder.length <= 100
1 <= preorder[i] <= 10^8
The values of preorder are distinct.

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What is a Python code to find a binary search tree with the given requirements?
assistant
#Here is Python code to find a binary search tree with the given requirements.

# Definition for a binary tree node.
# class TreeNode:
#     def __init__(self, val=0, left=None, right=None):
#         self.val = val
#         self.left = left
#         self.right = right
class Solution:
    def bstFromPreorder(self, preorder: List[int]) -> TreeNode:
        
        if len(preorder) == 0:
            return None
        
        return self.helper(preorder,0,len(preorder))
        
    def helper(self,preorder,start,end):
        # print(start,end,preorder[start:end])
        if start >= end:
            return None
        
        split = start + 1
        root = TreeNode(preorder[start])
        
        while split < end and preorder[start] > preorder[split]:
            split+=1
        
        root.left = self.helper(preorder,start + 1,split)
        root.right = self.helper(preorder,split,end)
        return root