#!/usr/bin/perl -w

my @test = ((1..3), 5, (7..9), (11..12), (17..19));

sub range {
   @_=sort{$a<=>$b}@_;@r=($l)=$_[0];
   map{if(abs$l-$_>1){push@r,$r=$_;
   $r[-2].="~$l";}$l=$_;}@_;@r;
   
}

my @ranged = range(@test);

print "@test \n";    # prints 1 2 3 5 7 8 9 11 12 17 18 19
print "@ranged \n";  # prints 1~3 5~5 7~9 11~12 17