Solutions to challenge 20

4 files changed, 84 insertions, 0 deletions

diff --git a/challenge-020/roger-bell-west/perl5/ch-1.pl b/challenge-020/roger-bell-west/perl5/ch-1.pl
new file mode 100755
index 0000000000..5816299fbe
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+++ b/challenge-020/roger-bell-west/perl5/ch-1.pl
@@ -0,0 +1,14 @@
+#! /usr/bin/perl
+
+use strict;
+use warnings;
+
+use List::Util qw(pairmap);
+
+foreach my $in (@ARGV) {
+  print join(' ',splitchange($in)),"\n";
+}
+
+sub splitchange {
+  return pairmap {$a.$b} shift =~ /(.)(\g1*)/g;
+}
diff --git a/challenge-020/roger-bell-west/perl5/ch-2.pl b/challenge-020/roger-bell-west/perl5/ch-2.pl
new file mode 100755
index 0000000000..36ab4ba1c2
--- /dev/null
+++ b/challenge-020/roger-bell-west/perl5/ch-2.pl
@@ -0,0 +1,29 @@
+#! /usr/bin/perl
+
+use strict;
+use warnings;
+
+use Math::BigInt lib => 'GMP';
+use Math::Prime::Util qw(divisors);
+use List::Util qw(sum);
+
+my $a=Math::BigInt->new(1);
+while (1) {
+  $a++;
+  my @a=grep {$_ != $a} divisors($a);
+  unless (@a) {
+    next;
+  }
+  my $b=sum(@a);
+  if ($b <= $a) {
+    next;
+  }
+  my @b=grep {$_ != $b} divisors($b);
+  unless (@b) {
+    next;
+  }
+  my $aa=sum(@b);
+  if ($aa == $a) {
+    print "$a, $b\n";
+  }
+}
diff --git a/challenge-020/roger-bell-west/perl6/ch-1.p6 b/challenge-020/roger-bell-west/perl6/ch-1.p6
new file mode 100755
index 0000000000..f369c23c39
--- /dev/null
+++ b/challenge-020/roger-bell-west/perl6/ch-1.p6
@@ -0,0 +1,9 @@
+#! /usr/bin/perl6
+
+for @*ARGS -> $in {
+  say join(' ',splitchange($in));
+}
+
+sub splitchange ($in) {
+   return map {$_.Str}, $in ~~ m:g/(.) {} :my $c = $0; ($c*)/;
+}
diff --git a/challenge-020/roger-bell-west/perl6/ch-2.p6 b/challenge-020/roger-bell-west/perl6/ch-2.p6
new file mode 100755
index 0000000000..9f095df46b
--- /dev/null
+++ b/challenge-020/roger-bell-west/perl6/ch-2.p6
@@ -0,0 +1,32 @@
+#! /usr/bin/perl6
+
+my $a=1;
+while (1) {
+  $a++;
+  my @a=divisors_unself($a);
+  unless (@a) {
+    next;
+  }
+  my $b=@a.sum;
+  if ($b <= $a) {
+    next;
+  }
+  my @b=divisors_unself($b);
+  unless (@b) {
+    next;
+  }
+  my $aa=@b.sum;
+  if ($aa == $a) {
+    print "$a, $b\n";
+  }
+}
+
+sub divisors_unself ($k) {
+  my @d=(1);
+  for 2..$k/2.Int -> $d {
+    if ($k % $d == 0) {
+      push @d,$d;
+    }
+  }
+  return @d;
+}
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