Binary Search Trees

This page contains various implementations of different Binary Search Trees (BSTs).

Simple BST (no balancing)

• bst.py (PY)
  • Features: insert, find, delete_min, ASCII art
• bstsize.py (PY)
  • Imports and extends bst.py
  • Augmentation to compute subtree sizes
• bstsize_r.py (PY)
  • Recursive version from recitation for computing subtree sizes
  • Features: insert, find, rank, delete

AVL tree

• avl.py (PY)
  • Imports and extends bst.py
  • Features: insert, find, delete_min, ASCII art

Testing

Both bst.py and avl.py (as well as bstsize.py) can be tested interactively from a UNIX shell as follows:

• python bst.py 10 — do 10 random insertions, printing BST at each step
• python avl.py 10 — do 10 random insertions, printing AVL tree at each step

Alternatively, you can use them from a Python shell as follows:

>>> import bst
>>> t = bst.BST()
>>> print t
 >>> for i in range(4): ...   t.insert(i); ... >>> print t 0 /\  1  /\   2   /\    3    /\ >>> t.delete_min() >>> print t 1 /\  2  /\   3   /\

>>> import avl
>>> t = avl.AVL()
>>> print t
 >>> for i in range(4): ...   t.insert(i); ... >>> print t   1  / \ 0  2 /\ /\     3     /\ >>> t.delete_min() >>> print t   2  / \ 1  3 /\ /\