public Node toBST(int preorder[]){
        Index index = new Index();
        return toBST(preorder,Integer.MIN_VALUE,Integer.MAX_VALUE,index);
    }
http://www.geeksforgeeks.org/construct-bst-from-given-preorder-traversa/
Test case
empty array
1,2 or more elements in the array
src/com/interview/tree/ConstructBSTFromPreOrderArray.java