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] 8 / \ 5 10 / \ \ 1 7 12


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

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