Kolakoski

Score: 71.16 (pass)

#!perl -l
@.=@ARGV;$.=1,s/./$.[$.^=1]x$&/ge,$_.=$.[!$.]until/.{$.[2]}/;print$&

Score: 72.17 (pass)

#!perl -l
@.=@ARGV;$.=1,s/./$.[$.^=1]x$&/ge,$_.=$.[$.^1]until/.{$.[2]}/;print$&

Score: 74.16 (fail)

#!perl -l
@.=@ARGV;$.=1,s/./$.[$.^=1]x$&/ge,$_.=$.[$.]until/(.{$.[2]})../;print$1

Score: 74.26 (fail)

#!perl -l
@a=@ARGV;do{$x=1;s/./$a[$x^=1]x$&/ge;$_.=$a[$x]}until/.{$a[2]}/;print$&

Score: 80.26 (pass)

#!perl -l
@a=@ARGV;push@s,($a[$x++%2])x($s[$i++]||shift)until@s>500;print@s[0..pop()-1]

Score: 81.25 (fail)

#!perl -lw
@a=@ARGV;push@s,($a[$^W^=1])x($s[$i++]||shift)until@s>500;print@s[0..pop()-1]

Score: 81.25 (pass)

#!perl -l
@a=@ARGV;push@s,($a[$x++%2])x($s[$i++]||shift)until@s>500;print@s[0..pop()-1];

Score: 92.27 (pass)

#!perl -l
$l=pop;@a=@ARGV;$_=$a[0]x$a[0].pop;do{$x=1}until s/./($a[$x^=1])x$&/ge&&/.{$l}/;
print$&;

Score: 92.27 (pass)

#!perl -l
$l=pop;@a=@ARGV;$_=$a[0]x$a[0].pop;do{$x=1}until s/./($a[$x^=1])x$&/ge&&/.{$l}/;
print$&;