http://www.perlmonks.org?node_id=849154


in reply to Code Golf: Four is magic

Well, I'm not much of a golfer, but here is a proof of concept (at a whopping 258 strokes) that goes up to 999 nonillion... using spelling in Lingua::EN::Numbers (limiting to 0..99 is too boring)

# Update: 222 strokes by using a bareword and (for the fun of it) supp
+ort up to undecillion 10^36 (costs no extra chars due to bareword tri
+ck)
for f in 0 4 12 99 1024 1000024 999999999999999999999999999999999; do 
+echo $f | \
perl -E'@x=a33544355436688779880066555766=~/./g;$_=<>;chop;while(($a=$
+_)-4){split//,b999aabb87780;$x=4*!$_;$x+=hex(pop@_)*!!-$&+!!$1*($x[$1
+]+7)+$x[$2+20]+$x[$3]while s/(.??)([^1]?)(1?.)$//;say"$a is $x.";$_=$
+x}say"4 is magic."' ; \
echo; done

# Update: 224 strokes by including the suggested =~/./g shortcut and m
+oving output around a bit
perl -E'@x="033544355436688779880066555766"=~/./g;$_=<>;chop;while(($a
+=$_)-4){split//,"99aabb87780";$x=4*!$_;$x+=hex(pop@_)*!!-$&+!!$1*($x[
+$1]+7)+$x[$2+20]+$x[$3]while s/(.??)([^1]?)(1?.)$//;say"$a is $x.";$_
+=$x}say"4 is magic."'

# Update: 229 strokes by moving some conditionals into the regex
perl -E'@x=split//,"033544355436688779880066555766";$_=<>;chop;print;w
+hile($_-4){split//,"99aabb87780";$x=4*!$_;$x+=hex(pop@_)*!!-$&+!!$1*(
+$x[$1]+7)+$x[$2+20]+$x[$3]while s/(.??)([^1]?)(1?.)$//;say" is $x.";p
+rint$_=$x}say" is magic."'

# Update: Ah, ha! 239 strokes:  !!-$& will do it
perl -E'@x=split//,"0335443554366887798866555766";$_=<>;chop;print;whi
+le($_-4){split//,"99aabb87780";$x=4*!$_;$x+=hex(pop@_)*!!-$&+!!$1*($x
+[$1]+7)+($2>1?$x[$2+18]+$x[$3]:$x[$2.$3])while s/(.??)(.?)(.)$//;say"
+ is $x.";print$_=$x}say" is magic."'

# Update: 242 strokes, and works :), stealing some ideas from haarg & 
+thundergnat
perl -E'@x=split//,"0335443554366887798866555766";$_=<>;chop;print;whi
+le($_-4){split//,"99aabb87780";$x=4*!$_;$x+=hex(pop@_)*!!(0+$&)+!!$1*
+($x[$1]+7)+($2>1?$x[$2+18]+$x[$3]:$x[$2.$3])while s/(.??)(.?)(.)$//;s
+ay" is $x.";print$_=$x}say" is magic."'

# Update: Down to 258 strokes
perl -E'@x=split//,"0335443554366887798866555766";$_=<>;chop;print;whi
+le($_!=4){split//,"99aabb87780";$_?do{$x=0;while(s/(.??)(.?)(.)$//){$
+x+=hex(pop@_)*(0+$&?1:0)+($1?$x[$1]+7:0)+($2>1?$x[$2+18]+$x[$3]:$x[$2
+.$3])}}:($x=4);say" is $x.";print$_=$x}say" is magic."'

# 261 strokes:
perl -E'@x=split//,"0335443554366887798866555766";$_=<>;chop;print;whi
+le($_!=4){@m=split//,"99aabb87780";$_?do{$x=0;while(s/(.??)(.?)(.)$//
+){$x+=hex(pop@m)*(0+$&?1:0)+($1?$x[$1]+7:0)+($2>1?$x[$2+18]+$x[$3]:$x
+[$2.$3])}}:($x=4);say" is $x.";print$_=$x}say" is magic."'

999999999999999999999999999999999 is 321.
321 is 21.
21 is 9.
9 is 4.
4 is magic.

[download]

Good Day,
    Dean

Replies are listed 'Best First'.
Re^2: Code Golf: Four is magic
by Haarg (Priest) on Jul 13, 2010 at 17:25 UTC
    A couple small improvements: 
    perl -E'@x=split//,"0335443554366887798866555766";$_+=<>;print;while($
+_!=4){split//,"99aabb87780";$_?do{$x=0;$x+=hex(pop)*!!$&+($1&&$x[$1]+
+7)+($2>1?$x[$2+18]+$x[$3]:$x[$2.$3])while s/(.??)(.?)(.)$//}:($x=4);s
+ay" is $x.";print$_=$x}say" is magic."'

    [download]
[reply]
[d/l]

      That actually has problems with large numbers (> native integer ?) Once it gets over 64 bits on my machine it converts to scientific notation... which throws off the conversion.

      Never mind. Broken

      Here's my whack at it - 232 strokes

      perl -E'@x=split//,"4335443554366887798866555766";$_=<>;chop;print;whi
+le($_-4){split//,"99aabb87780";$x=0;$x+=hex(pop)*!!$&+($1&&$x[$1]+7)+
+($2>1?$x[$2+18]+$x[$3]:$x[$2.$3])while s/(.??)(.?)(.)$//;say" is $x."
+;print$_=$x}say" is magic."'

__END__
999999999999999999999999999999999
999999999999999999999999999999999 is 231.
231 is 19.
19 is 8.
8 is 5.
5 is 4.
4 is magic.

      [download]
[reply]
[d/l]

        Doesn't seem to work right -- ($1&&$x[$1]+7) adds 7 too often and !!$& has issues with "000".

        # 123456789_123456789_1
# onemilliontwentyfour
# onethousandtwentyfour

echo 1000024 | perl duelafn.pl
1000024 is 20.
20 is 6.
6 is 3.
3 is 5.
5 is 4.
4 is magic.

echo 1024 | perl duelafn.pl
1024 is 21.
21 is 9.
9 is 4.
4 is magic.

echo 1000024 | haarg.pl
1000024 is 13.
13 is 8.
8 is 5.
5 is 4.
4 is magic.

echo 1024 | haarg.pl
1024 is 13.
13 is 8.
8 is 5.
5 is 4.
4 is magic.

echo 1000024 | perl thundergnat.pl
1000024 is 17.
17 is 9.
9 is 4.
4 is magic.

echo 1024 | perl thundergnat.pl
1024 is 13.
13 is 8.
8 is 5.
5 is 4.
4 is magic.

        [download]

        Update tracked doiwn more details of the bugs.

        Good Day,
            Dean

[reply]
[d/l]
[select]
Re^2: Code Golf: Four is magic
by thundergnat (Deacon) on Jul 14, 2010 at 17:27 UTC

    A modest improvement on your 229:
    227 strokes

    perl -E'@x="033544355436688779880066555766"=~/./g;$_=<>;chop;print;whi
+le($_-4){split//,"99aabb87780";$x=4*!$_;$x+=hex(pop@_)*!!-$&+!!$1*($x
+[$1]+7)+$x[$2+20]+$x[$3]while s/(.??)([^1]?)(1?.)$//;say" is $x.";pri
+nt$_=$x}say" is magic."'

    [download]
[reply]
[d/l]

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