###Challenge 11
Language Version: Python 2.7.12
Algorithms ref:
http://www.algolist.net/Data_structures/Binary_search_tree/Removal
$ python bst.py
Please type in a list of node integer, seperated by space.
5 2 1 3 12 9 21 19 36
Original bst list:
[5, 2, 1, 3, 12, 9, 21, 19, 36]
Please type in key(s) you want to delete:
(you could type in one int, or a list of int like following, if the key is not in bst, you will also be notified.)
5 7 2 19
key 7 not found.
New bst list:
[9, 3, 1, 12, 21, 36]
###Testing
$ python unit_test.py