public static void main(String args[]) {
        int preorder[] = {10, 5, 3, 21, 20, 18, 9 , 16};
        int inorder[] = {3, 5, 21, 10, 18, 9, 20, 16};
        PrintPostOrderFromPreOrderInOrder ppp = new PrintPostOrderFromPreOrderInOrder();
        int postorder[] = ppp.postOrder(preorder, inorder);
        for(int i : postorder) {
            System.out.print(i + " ");
        }
    }
Date 11/02/2015
@author Tushar Roy

Given a preorder/inorder traversal of binary tree create postorder traversal of binary tree
without creating the tree

Time complexity - O(n)

References
http://www.geeksforgeeks.org/print-postorder-from-given-inorder-and-preorder-traversals/
src/com/interview/tree/PrintPostOrderFromPreOrderInOrder.java