tasks a-s

Task/Run-length-encoding/Perl/run-length-encoding-1.pl

@@ -0,0 +1,13 @@
+# functional approach (return the encoded or decoded string)
+sub encode {
+  (my $str = shift) =~ s {(.)(\1*)} {length($&).$1}gse;
+  return $str; }
+sub decode {
+  (my $str = shift) =~ s {(\d+)(.)} {$2 x $1}gse;
+  return $str;}
+
+# procedural approach (modify the argument in place)
+sub encode {
+  $_[0] =~ s {(.)(\1*)} {length($&).$1}gse; }
+sub decode {
+  $_[0] =~ s {(\d+)(.)} {$2 x $1}gse; }

Task/Run-length-encoding/Perl/run-length-encoding-2.pl

@@ -0,0 +1,14 @@
+sub encode
+ {my $str = shift;
+  $str =~ s {(.)(\1{0,254})} {pack("C",(length($2) + 1)) . $1 }gse;
+  return $str;}
+
+sub decode
+{
+     my @str = split //, shift;
+     my $r = "";
+     foreach my $i (0 .. scalar(@str)/2-1) {
+	 $r .= $str[2*$i + 1] x unpack("C", $str[2*$i]);
+     }
+     return $r;
+}