Solution for 20.2 in P6 and P5

2 files changed, 75 insertions, 0 deletions

diff --git a/challenge-020/joelle-maslak/perl5/ch-2.pl b/challenge-020/joelle-maslak/perl5/ch-2.pl
new file mode 100755
index 0000000000..dc240d181a
--- /dev/null
+++ b/challenge-020/joelle-maslak/perl5/ch-2.pl
@@ -0,0 +1,49 @@
+#!/usr/bin/env perl
+
+use strict;
+use warnings;
+
+use v5.22;
+
+# Turn on method signatures
+use feature 'signatures';
+no warnings 'experimental::signatures';
+
+use List::Util qw(max sum);
+use integer;
+
+MAIN: {
+    my @factors;
+    my @results;
+
+    my $i = 2;
+    while ( $i++ ) {
+        my $sum = factorsum($i);
+        $factors[$i] = $sum;
+
+        if ( ( $sum > 1 ) && ( $sum < $i ) ) {
+            if ( $i == $factors[$sum] ) {
+                say "$sum $i";
+                exit;
+            }
+        }
+    }
+
+    say sum @results;
+}
+
+sub factorsum($num) {
+    my @f;
+    my $sqrt = sqrt $num;
+
+    push @f, 1;
+    if ( $sqrt * $sqrt == $num ) { push @f, $sqrt; }
+
+    for ( my $i = 2; $i < $sqrt; $i++ ) {
+        if ( $num % $i != 0 ) { next; }
+        push @f, $i, $num / $i;
+    }
+
+    return sum @f;
+}
+
diff --git a/challenge-020/joelle-maslak/perl6/ch-2.p6 b/challenge-020/joelle-maslak/perl6/ch-2.p6
new file mode 100755
index 0000000000..6a2c4f8970
--- /dev/null
+++ b/challenge-020/joelle-maslak/perl6/ch-2.p6
@@ -0,0 +1,26 @@
+#!/usr/bin/env perl6
+use v6;
+use experimental :cached;
+
+# Smallest pair is a confusing term.  Is it (A, B) where a is the
+# smallest A, or is it where A+B is the smallest A+B?  I'm going with
+# the smallest A.
+
+MAIN: {
+    my $amicable =
+        grep { factorsum($^a) != $^a },
+        grep { $^a == factorsum(factorsum($^a)) },
+        2..∞;
+
+    say $amicable[0] ~ " " ~ factorsum($amicable[0]);;
+}
+
+sub factorsum($num) is cached {
+    return sum
+        unique :with(&[==]),
+        grep { $^a != $num},
+        map  { |($^a, $num / $^a) },
+        grep { $num %% $^a },
+        1..( Int(sqrt($num)) );
+}
+