1.1 --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
     1.2 +++ b/examples/fib.py	Sat Mar 05 15:27:15 2011 +0100
     1.3 @@ -0,0 +1,40 @@
     1.4 +"""
     1.5 +Name: fib - Fibonacci number machine
     1.6 +Description: Recursive and DP-based calculation of Fibonacci numbers.
     1.7 +
     1.8 +Author: Eugen Sawin <sawine@me73.com>
     1.9 +"""
    1.10 +
    1.11 +def main():
    1.12 +    args = parse_args()
    1.13 +    if args.d:
    1.14 +        fun = fib_dynamic
    1.15 +    else:
    1.16 +        fun = fib
    1.17 +    print fun(args.n)
    1.18 +
    1.19 +def fib(n):
    1.20 +    if n > 1:
    1.21 +        return fib(n-1) + fib(n-2)
    1.22 +    else:
    1.23 +        return n
    1.24 +
    1.25 +def fib_dynamic(n):
    1.26 +    f = (0, 1)
    1.27 +    for i in xrange(2, n + 1):
    1.28 +        f = (f[1], sum(f))
    1.29 +    if n < 1:
    1.30 +        return n
    1.31 +    else:
    1.32 +        return f[1]
    1.33 +
    1.34 +from argparse import ArgumentParser
    1.35 +
    1.36 +def parse_args():
    1.37 +    parser = ArgumentParser(description='Returns the Fibonacci number for a given number n.')
    1.38 +    parser.add_argument('n', type=int, help='Fib(n)')
    1.39 +    parser.add_argument('-d', action='store_true', help='dynamic programming')
    1.40 +    return parser.parse_args()
    1.41 +
    1.42 +if __name__ == "__main__":
    1.43 +    main()