Kolakoski

Score: 84.26 (pass)

#!perl -l
($s,$t,$n)=@ARGV;$_=$s.$t;$p="$t$s"x$n,s/./chop($p)x$&/eg until/(.{$n})./;print$1

Score: 85.26 (pass)

#!perl -l
($s,$t,$n)=@ARGV;$_=$s.$t;$p="$t$s"x$n,s/./chop($p)x$&/eg until/(.{$n})./;print$1;