give array integer preorder represent preorder traversal BST ie binary search tree construct tree return rootIt guarantee possible find binary search tree give requirement give test casesA binary search tree binary tree node descendant Nodeleft value strictly Nodeval descendant Noderight value strictly great NodevalA preorder traversal binary tree display value node traverse Nodeleft traverse Noderight Example 1input preorder 85171012output 851017null12example 2input preorder 13Output 1null3 Constraints1 preorderlength 1001 preorderi 1000all value preorder unique