Combining that with another stroke saved by replacing the stupid ++$g, $g-1 stuff 
push@a,/./g}{print$s{-1+map{$u{$_}||=$a[$_]+$s{$g}for
grep$a[$_]*!$s{$_},$g+$.,$g-($g%$.>0),$g-$.*($g>=$.),$g+($g%$.
<$.-1);($g)=sort{$u{$a}-$u{$b}}keys%u;$s{$g}=delete$u{$g}}@a}

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In reply to Re^2: Advent of Code, Day 15, golfed! by Jasper
in thread Advent of Code, Day 15, golfed! by Jasper

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