public void printVertical(Node root){
        Map<Integer,List<Node>> map = new TreeMap<Integer,List<Node>>();
        populateMap(root,map,0);
        printLevel(map);
    }
http://www.geeksforgeeks.org/print-binary-tree-vertical-order-set-2/
src/com/interview/tree/VerticalTreePrinting.java