public static void main(String args[]){
        int in[] = {-6,0,15,10,3,25,2};
        int pre[] = {10,15,-6,0,25,3,2};
        ConstructTreeFromInOrderPreOrder ct = new ConstructTreeFromInOrderPreOrder();
        Node root = ct.createTree(in, pre);
        BinaryTreeToSortedLinkList bt = new BinaryTreeToSortedLinkList();
        root = bt.toSortedLinkList(root);
        bt.print(root);
    }
http://www.careercup.com/question?id=6241652616200192
Test cases:
0,1 or more nodes in the tree
src/com/interview/tree/BinaryTreeToSortedLinkList.java