Topological Sort

Score: 64.58 (pass)

#!perl -ln0
/ \Q$&/||print$1while s/(
|(?= ?\G))\Q$&/ 
/g,/(\S+) /g/$#+

Score: 64.58 (pass)

the dual solution

#!perl -ln0
/(?<= )\Q$&
/||print$1while s/(
|\G)\Q$&/ 
/g,/(\S+) /g/$#+

Score: 65.50 (pass)

#!perl -ln0
/ \Q$&\E$/m||print$&while s/(^|\G)\Q$&\E\s/
/mg,/\S+/g;1/!//

Score: 65.50 (pass)

Do everything with one statement A pity I needed to add that () But maybe distinguishing $1 and $& will prove useful

#!perl -ln0
/ \Q$&\E$/m||print$&while s/(^|\G)\Q$&\E\s/
/mg,/(\S+)/g/$#+

Score: 67.52 (fail)

fails if the same singleton can appear multiple times in the input. Needs rule clarification

#!perl -ln0
/(?!\G) \Q$&
/||print($&)+s/^(\Q$&\E\s)+/
/mgwhile/\S+/g;1/!//

Score: 70.48 (pass)

#!perl -ln0
s/\G \Q$&
/
/+/ \Q$&
/||print$&while s/^\Q$&\E\s//mg,/\S+/g;1/!//

Score: 71.49 (pass)

#!perl -ln0
s/\G \Q$&
/
/-/ \Q$&
/||print($&)+s/^\Q$&\E\s//mgwhile/\S+/g;1/!//

Score: 71.51 (pass)

#!perl -p0
s/\G \Q$&
/
/+/ \Q$&
/ or$\.="$&
",s/^\Q$&\E\s//mgwhile/\S+/g;1/!//

Score: 72.49 (pass)

#!perl -ln0
s/\G \Q$&
/
/+/ \Q$&
/||print($&)+s/^\Q$&\E\s/
/mgwhile/\S+/g;1/!//

Score: 73.49 (pass)

#!perl -ln0
s/\G \Q$&
/
/+/ \Q$&
/||print($&)+s/^\Q$&\E\s/\n/mgwhile/\S+/g;1/!//

Score: 74.54 (pass)

#!perl -ln0
/^(.+) (?!\1
)\Q$&
/m||print($&)+s/^(\Q$&\E\s)+/
/mgwhile/\S+/g;1/!//

Score: 76.54 (pass)

#!perl -ln0
/^(?!\Q$&\E ).* \Q$&
/m||print($&)+s/^(\Q$&\E\s)+/
/mgwhile/\S+/g;1/!//

Score: 78.50 (fail)

This shows a problem with the test program

#!perl -Xln0
/^(?!\Q$&\E ).* \Q$&
/m||print$&|s/^(\Q$&\E\s)+/
/mgwhile/^\S+/gm;exit//

Score: 78.53 (pass)

#!perl -ln0
/^(?!\Q$&\E ).* \Q$&
/m||print($&)+s/^(\Q$&\E\s)+/
/mgwhile/^\S+/gm;1/!//

Score: 80.51 (pass)

#!perl -Xln0
/^(?!\Q$&\E ).* \Q$&
/m||print($&)+s/^(\Q$&\E\s)+/
/mgwhile/^\S+/gm;exit//

Score: 81.51 (fail)

#!perl -Xln0
/^(?!\Q$&\E ).* \Q$&
/m||print"$&"|!s/^(\Q$&\E\s)+/
/mgwhile/^\S+/gm;exit//

Score: 81.51 (pass)

#!perl -Xln0
/^(?!\Q$&\E ).* \Q$&
/m||print"$&",!s/^(\Q$&\E\s)+/
/mgwhile/^\S+/gm;exit//

Score: 83.52 (fail)

#!perl -Xln0
/^(?!(\Q$&\E) ).* \Q$&
/m||print"$&"|!s/^(\Q$&\E\s)+/
/mgwhile/^\S+/gm;exit//

Score: 86.51 (fail)

#!perl -Xln0
$;=$&and/^(?!\Q$;\E ).* \Q$;
/m||s/^(\Q$;\E\s)+/
/mg*print$;while/^\S+/gm;exit//

Score: 88.51 (fail)

#!perl -Xln0
$;=$+and/^(?!\Q$;\E ).* \Q$;
/m||s/^(\Q$;\E\s)+/
/mg*print$;while/^(\S+)/gm;exit//

Score: 90.53 (fail)

#!perl -ln0
$;=$+and/^(?!\Q$;\E ).* \Q$;
/m||s/^(\Q$;\E\s)+/
/mg*print$;while/^(\S+)/gm;//&&die}{

Score: 91.53 (fail)

#!perl -ln0
$;=$+and/^(?!\Q$;\E ).* \Q$;
/m||s/^(\Q$;\E\s)+/
/mg*print$;while/^(\S+)/gm;/./&&die}{

Score: 102.48 (fail)

#!perl -ln0
$;=$+and/ \Q$;
/||s/^\Q$;\E\s/
/mg*print$;while/^(\S+)/gm;print$+while s/^(\S+) \1$//m;/./&&die}{

Score: 104.49 (fail)

#!perl -ln0
$;=$+and/ \Q$;
/||s/^ ?\Q$;\E\s/
/mg*print$;while/^(\S+)/gm;print$+while s/^(\S+) \1$//m;/./&&die}{