Objectives: You will gain experience BST performance and implementation
To start the lab: Download and unzip the file:
Part A: Run the timeBinarySearchTree.py program that:
creates a list, evenList, that holds 3,000 sorted, even values (e.g., evenList = [0, 2, 4, 6, 8, ..., 5996, 5998])
puts (adds) all the evenList items into an initially empty BinarySearchTree object, bst
times the searches (in) bst for target values 0, 1, 2, 3, 4, ..., 5998, 5999 so half of the searches are successful and
half are unsuccessful
a) How long does it take to search for target values from 0, 1, 2, 3, 4, ..., 5998, 5999?
b) Explain why these searches take so long. (Hint: consider the shape of the BinarySearchTree bst)
c) Uncomment the “shuffle(evenList)” which randomizes the items in evenList. Now how long does it take
to search for target values from 0, 1, 2, 3, 4, ..., 5998, 5999?
d) Explain why these searches take so little time.
e) What is the search time with the timeOpenAddrHashDictSearch.py program? Why is it faster?
After you have answered the above questions, raise your hand and explain your answers.
Part B:
a) Complete the recursive height method in the BinarySearchTree class (model it after one of the traversals).
Uncomment the call to the height method at the end of the timeBinarySearchTree.py program. What is
the height of bst if we are shuffling the evenList?
b) What would be the shortest possible height for a binary tree with 3,000 items?
c) Why was it necessary to raise the recursion limit with the statement: sys.setrecursionlimit(10000)?
After you have completed the height method and answered the above questions, raise your hand and explain
your answers.
Data Structures (CS 1520) Lab 9 Name:___________________________
Lab 9 - 1
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