solution to 2.72

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+#lang racket
+
+#|
+Q:
+
+Consider the encoding procedure that you designed in exercise 2.68. What is the order of growth
+in the number of steps needed to encode a symbol? Be sure to include the number of steps needed
+to search the symbol list at each node encountered. To answer this question in general is difficult. 
+
+Consider the special case where the relative frequencies of the n symbols are as described in 
+exercise 2.71, and give the order of growth (as a function of n) of the number of steps needed
+to encode the most frequent and least frequent symbols in the alphabet. 
+|#
+
+#|
+A.
+
+encode-symbol, has to go down to the last level, n is the depth of the tree, where n
+is the number of symbols. On every node, it cons'es a number. Also there is the member? function
+which spends max of n steps to find out if a given symbol is a member of the set. This is done for
+every symbol in the message. So the worst case growth is of the order O(n * n).
+|#