5 files changed, 61 insertions, 0 deletions
diff --git a/challenge-220/arne-sommer/blog.txt b/challenge-220/arne-sommer/blog.txt
new file mode 100644
index 0000000000..b651a9bf4b
--- /dev/null
+++ b/challenge-220/arne-sommer/blog.txt
@@ -0,0 +1 @@
+https://raku-musings.com/squarefully-common.html
diff --git a/challenge-220/arne-sommer/raku/ch-1.raku b/challenge-220/arne-sommer/raku/ch-1.raku
new file mode 100755
index 0000000000..cf1a0759e2
--- /dev/null
+++ b/challenge-220/arne-sommer/raku/ch-1.raku
@@ -0,0 +1,9 @@
+#! /usr/bin/env raku
+
+unit sub MAIN (*@words where @words.elems > 1 && all(@words) ~~ /^<[a..zA..Z]>+$/, :v(:$verbose));
+
+my $set = [(&)] @words>>.lc>>.comb;
+
+say ":Set: { $set.raku }" if $verbose;
+
+say '(' ~ $set.keys.sort.map({ '"' ~ $_ ~ '"' }).join(", ") ~ ')';
diff --git a/challenge-220/arne-sommer/raku/ch-2.raku b/challenge-220/arne-sommer/raku/ch-2.raku
new file mode 100755
index 0000000000..fad02576a5
--- /dev/null
+++ b/challenge-220/arne-sommer/raku/ch-2.raku
@@ -0,0 +1,21 @@
+#! /usr/bin/env raku
+
+unit sub MAIN (*@ints where @ints.elems > 1 && all(@ints) ~~ Int);
+
+my $length = @ints.elems;
+my @squareful;
+
+PERM-LOOP:
+for @ints.permutations.unique(:with(&[eqv])) -> @permutation
+{
+  for 0 .. $length -2 -> $index
+  {
+    my $sum  = @permutation[$index] + @permutation[$index +1];
+    my $root = $sum.sqrt;
+    next PERM-LOOP unless $root.Int == $root;
+  }
+
+  push(@squareful, @permutation);
+}
+
+say @squareful;
diff --git a/challenge-220/arne-sommer/raku/common-characters b/challenge-220/arne-sommer/raku/common-characters
new file mode 100755
index 0000000000..cf1a0759e2
--- /dev/null
+++ b/challenge-220/arne-sommer/raku/common-characters
@@ -0,0 +1,9 @@
+#! /usr/bin/env raku
+
+unit sub MAIN (*@words where @words.elems > 1 && all(@words) ~~ /^<[a..zA..Z]>+$/, :v(:$verbose));
+
+my $set = [(&)] @words>>.lc>>.comb;
+
+say ":Set: { $set.raku }" if $verbose;
+
+say '(' ~ $set.keys.sort.map({ '"' ~ $_ ~ '"' }).join(", ") ~ ')';
diff --git a/challenge-220/arne-sommer/raku/squareful b/challenge-220/arne-sommer/raku/squareful
new file mode 100755
index 0000000000..fad02576a5
--- /dev/null
+++ b/challenge-220/arne-sommer/raku/squareful
@@ -0,0 +1,21 @@
+#! /usr/bin/env raku
+
+unit sub MAIN (*@ints where @ints.elems > 1 && all(@ints) ~~ Int);
+
+my $length = @ints.elems;
+my @squareful;
+
+PERM-LOOP:
+for @ints.permutations.unique(:with(&[eqv])) -> @permutation
+{
+  for 0 .. $length -2 -> $index
+  {
+    my $sum  = @permutation[$index] + @permutation[$index +1];
+    my $root = $sum.sqrt;
+    next PERM-LOOP unless $root.Int == $root;
+  }
+
+  push(@squareful, @permutation);
+}
+
+say @squareful;