Lecture Notes on 09 November 2009

# Solution to Class Work on 9 Nov 2009
def func (n):
  if (n == 0):
    return 0
  else:
    return 2 * func(n - 1) + 1

# Iterative version of the above code
def funcIter (n):
  f = 0
  for i in range (1, n + 1):
    f = 2 * f + 1
  return f

# Recursive Fibonacci function
def fib (n):
  if ((n == 1) or (n == 2)):
    return 1
  else:
    return fib(n - 1) + fib(n - 2)

# Iterative Fibonacci function
def fibIter (n):
  f1 = 1
  f2 = 1
  f = 1
  for i in range (3, n + 1):
    f1 = f2
    f2 = f
    f = f1 + f2
  return f

# Recursive Towers of Hanoi function
def tower (n, source, spare, destination):
  if (n == 1):
    print "Move disk from", source, "to", destination
  else:
    tower (n - 1, source, destination, spare)
    print "Move disk from", source, "to", destination
    tower (n - 1, spare, source, destination)

def main():
  # Test first two functions
  for i in range (1, 10):
    print func(i), funcIter(i
  print

  # Test the two Fibonacci functions
  for i in range (1, 10):
    print fib(i), fibIter(i)
  print

  # Test Towers of Hanoi code
  for i in range (1, 6):
    print "Num disks = ", i
    tower (i, 'A', 'B', 'C')
    print 

main()