Re: Collaborative golf.

On Sat, Sep 14, 2002 at 08:47:23AM +0100, Piers Cawley wrote:
> So, whilst rambling, I came upon the calculations required to work out
> the date of easter for a given year (Gregorian calendar). Here it is
> expressed in perl.
> 
>     my $year = pop;
>     my $G = $year%19;
>     my $C = int($year/100);
>     my $H = ($C - $C/4 - int((8*$C+13)/25) + 19*$G + 15) %30;
>     $I = $H - int($H/28)*(1 - int($H/28) * int(29/($H+1)) * int(21-$G/11));
>     $J = ($year + int($year/4) + $I + 2 - $C + int($C/4))%7;
>     $L = $I - $J;
>     $month = 3 + int(($L+40)/44);
>     $day = $L + 28 - 31 * int($month/4);
>     printf("%d%02d%02d\n", $year, $month, $day);
> 
> I'm sure we can do better. But how *much* better?
> 
> My current best effort stands at 212 chars (scored by wc), which I'll
> post later today, unless someone has already done better.
> 
> Kudos will be given to anyone who does it in a regex...

Here's one that doesn't come anywhere near Perl, but it does have nicer
output and error checking - in 240 chars.

echo `echo $* '[ddsf[lfp[too early]Pq]s@1583>@ddd19%1+sg100/1+d3*4/12-sx8*5+25/5-sz5*4/lx-10-sdlg11*20+lz+lx-30%d[30+]s@0>@d[[1+]s@lg11<@]s@25=@d[1+]s@24=@se44le-d[30+]s@21>@dld+7%-7+[March ]smd[31-[April ]sm]s@31<@psnlmPpsn1z>p]splpx'|dc`

(That's all one line if someone gets it wrapped, but it probably doesn't
matter too much.)

I believe that most of the credit for this should go to Fred Avolio.
I've had it knocking around since the late 80s I think.

-- 
Paul Johnson - [email protected]
http://www.pjcj.net