Python Code Shortening

Question

I was trying to solve this problem here :- https://www.spoj.pl/problems/PHIVAL/

The questions asks you to output as many decimal digits of the golden ratio (1+sqrt(5))/2 as possible and also try to minimise the code length.

This is what I have right now. Can this code be made any shorter ?

from decimal import *
getcontext().prec=7050
print(1+Decimal(5).sqrt())/2

Flyaway

the fastest way to do it would be to have a webpage that spits out 1 million digits of phi and have your program just be echo curl mysite.com\phi :-) – Serpasil

Why set precision to 7050? Why not 9999? Just as short code-wise, but many more digits. – Magnification

@delnan It would exceed the timelimit. – Flyaway

@glowcoder .. very clever :) .. But that wouldn't work on the spoj. – Flyaway

For reference, codegolf.stackexchange.com has a whole bunch of these spoj.pl problems on them – Dobb

Answer 1

You can take out the space before the asterisk.

Update:

You added the part about insignificant whitespace, so I started thinking about a different approach. If whitespace isn't counted, you may be able to do something like this

print"1."+`map(len,"""      








       """.split("\n"))`[1::3]

It encodes each digit as a number of spaces on a line in a multi-line string constant. Obviously, you could add more lines to get more digits. It should run pretty fast, as there is very little calculation done. It uses 50 (update 2: 45) non-whitespace characters to produce any number of digits output.

Buddybuderus

Thanks. But the source length is counted as the number of non-white space characters. – Flyaway

@jack_carver: With the new information about white space, I came up with another approach that may give better results. – Buddybuderus

You can make any python code to just 44 characters (or 42 in python2) if white space is not counted pastebin.com/uHR9TwQT – Radiotransparent

Answer 2

Taking recursive's approach to an extreme, this uses just 19 non-whitespace characters:

print '1.%d'%len('                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          ')

Granted, the code required to generate the first 1000000 digits would be over 10^1000000 characters in length!

Deodar

Answer 3

Due to high score for short code, i think that best approach could be just

print 1

Bona

score(ndigits=1, codelen=6) -> 2500001, score(7050, 68) -> 227638 There must be "at least 1000 [digits] after the decimal point." – Vinosity

Answer 4

Well I tried javascript-ish approach, and it apparently doesn't work in Python:

import decimal
decimal.__dict__.values()[17]().prec = 7050
...

Looks like your code is pretty close to the shortest possible solution.

Villenage

Yes. But due to the varied nature of the formula I cannot exactly figure out the minimal source length. The best python solution there has a score of "307962" Where as mine gives "212528". – Flyaway