#lang racket

(require "ch2_3.rkt"
         rackunit)

;; Exercise 2.67.  Define an encoding tree and a sample message:
(define sample-tree
  (make-code-tree (make-leaf 'A 4)
                  (make-code-tree 
                   (make-leaf 'B 2)
                   (make-code-tree (make-leaf 'D 1)
                                   (make-leaf 'C 1)))))
(define sample-message '(0 1 1 0 0 1 0 1 0 1 1 1 0))

(check equal? (decode sample-message sample-tree) '(A D A B B C A))