stamp.py

# Define a procedure, stamps, which takes as its input a positive integer in
# pence and returns the number of 5p, 2p and 1p stamps (p is pence) required 
# to make up that value. The return value should be a tuple of three numbers 
# (that is, your return statement should be followed by the number of 5p,
# the number of 2p, and the nuber of 1p stamps).
#
# Your answer should use as few total stamps as possible by first using as 
# many 5p stamps as possible, then 2 pence stamps and finally 1p stamps as 
# needed to make up the total.
#
# (No fair for USians to just say use a "Forever" stamp and be done with it!)
#

def stamps(n):
    a = 0
    while 5 * a <= n:
        m = n-5*a
        a = a+1
        b = 0
        while 2 * b <= m:
            c = m-2*b
            b = b+1
    return (a-1,b-1,c)




print stamps(50)
#>>> (10, 0, 0)  # one 5p stamp, one 2p stamp and one 1p stamp
print stamps(5)
#>>> (1, 0, 0)  # one 5p stamp, no 2p stamps and no 1p stamps
print stamps(29)
#>>> (5, 2, 0)  # five 5p stamps, two 2p stamps and no 1p stamps
print stamps(0)
#>>> (0, 0, 0) # no 5p stamps, no 2p stamps and no 1p stamps