- Added solutions by Colin Crain.

5 files changed, 97 insertions, 0 deletions

diff --git a/challenge-070/colin-crain/blog.txt b/challenge-070/colin-crain/blog.txt
new file mode 100644
index 0000000000..0494fe274f
--- /dev/null
+++ b/challenge-070/colin-crain/blog.txt
@@ -0,0 +1 @@
+https://colincrain.wordpress.com/2020/07/27/exhibiting-gray-areas-in-character/
diff --git a/challenge-070/colin-crain/perl/ch-1.pl b/challenge-070/colin-crain/perl/ch-1.pl
new file mode 100644
index 0000000000..3138b36e74
--- /dev/null
+++ b/challenge-070/colin-crain/perl/ch-1.pl
@@ -0,0 +1,33 @@
+use warnings;
+use strict;
+use feature ":5.26";
+
+## ## ## ## ## MAIN:
+
+
+my ($str, $C, $O) = @ARGV;
+
+$str //= 'perlandraku';
+$C   //= 3;
+$O   //= 4;
+
+say "Count   $C";
+say "Offset  $O";
+say "Start   ", $str =~ s/\B/ /gr;       ## easier to see if we spread things out a bit
+
+$str = swap( $str, $C, $O );
+say "Result  ", $str =~ s/\B/ /gr;
+
+## ## ## ## ## SUBS:
+
+sub swap {
+    my ($str, $C, $O ) = @_;
+    my $N = length $str;
+
+    for my $i (1..$C) {
+        substr( $str, ($i+$O) % $N, 1) =
+            substr( $str, $i % $N, 1,
+                substr( $str, ($i+$O) % $N, 1));
+    }
+    return $str;
+}
diff --git a/challenge-070/colin-crain/perl/ch-2.pl b/challenge-070/colin-crain/perl/ch-2.pl
new file mode 100644
index 0000000000..1c1de658b4
--- /dev/null
+++ b/challenge-070/colin-crain/perl/ch-2.pl
@@ -0,0 +1,22 @@
+use warnings;
+use strict;
+use feature ":5.26";
+
+## ## ## ## ## MAIN:
+
+my $bits = shift @ARGV // 3;
+
+say "[ ", (join ', ', grey_code($bits)->@*), " ]";
+
+## ## ## ## ## SUBS:
+
+sub grey_code {
+    my $s = shift;
+    return [0, 1] if $s == 1;       ## edge case
+    return [ map { oct("0b".$_) } map {
+        my $n = $_;
+        my $fmt = '%0' . ($s-1) . "b";
+        my @gc = map {sprintf $fmt, $_} grey_code($s-1)->@*;
+        map { $n . $_ } $_ ? reverse @gc : @gc;
+    } (0,1)  ];
+}
diff --git a/challenge-070/colin-crain/raku/ch-1.raku b/challenge-070/colin-crain/raku/ch-1.raku
new file mode 100644
index 0000000000..a70e23676e
--- /dev/null
+++ b/challenge-070/colin-crain/raku/ch-1.raku
@@ -0,0 +1,26 @@
+sub MAIN ( Str $str is copy = 'abcdefgh', Int $C = 1, Int $O = 7) {
+
+
+    ## easier to see the results if we spread things out a bit
+    say "Count   $C";
+    say "Offset  $O";
+    say "Start   ",  $str.comb.join: ' ';
+
+    swap( $str, $C, $O );
+
+    say "Result  ", $str.comb.join: ' ';
+
+}
+
+
+## ## ## ## ## SUBS:
+
+sub swap ($str is rw, $C, $O) {
+    my $n = $str.chars;
+    for 1..$C -> $i {
+        my $tmp = $str.substr(($i+$O) % $n, 1);
+        $str.substr-rw(($i+$O) % $n, 1) = $str.substr-rw( $i % $n, 1 );
+        $str.substr-rw( $i % $n, 1 ) = $tmp;
+    }
+    return $str;
+}
diff --git a/challenge-070/colin-crain/raku/ch-2.raku b/challenge-070/colin-crain/raku/ch-2.raku
new file mode 100644
index 0000000000..87d381f973
--- /dev/null
+++ b/challenge-070/colin-crain/raku/ch-2.raku
@@ -0,0 +1,15 @@
+sub MAIN ( Int $bits where {$bits > 1} = 8) {
+
+    grey_code( $bits ).put;
+
+}
+
+sub grey_code ( $bits ) {
+    return (0,1) when $bits == 1;
+
+    return (0,1).map({
+        my $n = $_;
+        my @gc  = grey_code($bits-1).map: {$_.fmt('%0' ~ ($bits-1) ~ 'b')};
+        ($_ ?? reverse @gc !! @gc).map:{ $n ~ $_ };
+    }).flat.map:{ :2($_ )}
+}