1. Factorial Recursion Runtime Stack
F = lambda x : 1 if x == 0 else x*F(x-1)
print F(3)
F(3) waiting for 3*F(2)
F(2) waiting for 2*F(1)
F(1) waiting for 1*F(0)
F(0) returns 1

2. R 4 RR RL 2 5
RLL
RLR
RRL
RRR 1 3
RLLL
RLLR
RLRR
RLRL
# For the book BST code, do the following to get this tree:
numbers = [4,2,1,3,5]
intTree = BinaryTree()
for e in numbers:
intTree.insert(e)
# The next pages show the runtime stack for:
print intTree.inorder()
# and
print intTree.postorder()

3. def inorderHelper(self, r):
if r != None:
self.inorderHelper(r.left)
print r.element, " "
self.inorderHelper(r.right)
Inorder()
inorderHelper(R)
inorderHelper(RL), R.element, inorderHelper(RR)
inorderHelper(RLL), RL.element, inorderHelper(RLR)
inorderHelper(RLLL), RLL.element, inorderHelper(RLLR) 1 2
inorderHelper(RLRL), RLR.element, inorderHelper(RLRR) 3 4
inorderHelper(RRL),RR.element, inorderHelper(RRR) 5

4. def postorderHelper(self, root):
if root != None:
self.postorderHelper(root.left)
self.postorderHelper(root.right)
print root.element, " ”
Postorder(R)
postorderHelper(RL), postorderHelper(RR), R.element
postorderHelper(RLL), postorderHelper(RLR), RL.element
postorderHelper(RLLL), postorderHelper(RLLR), RLL.element 1
postorderHelper(RLRL), postorderHelper(RLRR), RLR.element 3 2
postorderHelper(RRL), postorderHelper(RRR), RR.element 5 4