public static void main(String args[]){
        int input[] = {20,10,14,15,17};
        BSTOneChildPreOrderTraversal boc = new BSTOneChildPreOrderTraversal();
        System.out.println(boc.isBST(input));
    }
http://www.geeksforgeeks.org/check-if-each-internal-node-of-a-bst-has-exactly-one-child/
src/com/interview/tree/BSTOneChildPreOrderTraversal.java