Add Perl solution

4 files changed, 100 insertions, 0 deletions

diff --git a/challenge-171/paulo-custodio/perl/ch-1.pl b/challenge-171/paulo-custodio/perl/ch-1.pl
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+#!/usr/bin/perl
+
+# Challenge 171
+#
+# Task 1: Abundant Number
+# Submitted by: Mohammad S Anwar
+#
+# Write a script to generate first 20 Abundant Odd Numbers.
+#
+# According to wikipedia,
+#
+#     A number n for which the sum of divisors σ(n) > 2n, or, equivalently, the
+#     sum of proper divisors (or aliquot sum) s(n) > n.
+#
+#
+# For example, 945 is the first Abundant Odd Number.
+#
+# Sum of divisors:
+# 1 + 3 + 5 + 7 + 9 + 15 + 21 + 27 + 35 + 45 + 63 + 105 + 135 + 189 + 315 = 975
+
+use Modern::Perl;
+use List::Util 'sum';
+
+sub divisors {
+    my($n) = @_;
+    my(@div_low, @div_high);
+    for (my $i = 1; $i <= sqrt($n); $i++) {
+        if ($n%$i == 0) {
+            push @div_low, $i;
+            unshift @div_high, $n/$i if $n/$i != $i;
+        }
+    }
+    return (@div_low, @div_high);
+}
+
+sub proper_divisors {
+    my($n) = @_;
+    my @div = divisors($n);
+    return @div[0..$#div-1];
+}
+
+sub is_abundant {
+    my($n) = @_;
+    return sum(proper_divisors($n)) > $n;
+}
+
+sub abundant_numbers {
+    my($N) = @_;
+    my @abundant;
+    my $n = 1;
+    while (@abundant < $N) {
+        push @abundant, $n if is_abundant($n);
+        $n++;
+    }
+    return @abundant;
+}
+
+@ARGV==1 or die "usage: ch-1.pl n\n";
+my $N = shift;
+say join ", ", abundant_numbers($N);
diff --git a/challenge-171/paulo-custodio/perl/ch-2.pl b/challenge-171/paulo-custodio/perl/ch-2.pl
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+++ b/challenge-171/paulo-custodio/perl/ch-2.pl
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+#!/usr/bin/perl
+
+# Challenge 171
+#
+# Task 2: First-class Function
+# Submitted by: Mohammad S Anwar
+#
+# Create sub compose($f, $g) which takes in two parameters $f and $g as
+# subroutine refs and returns subroutine ref i.e. compose($f, $g)->($x) =
+# $f->($g->($x))
+#
+# e.g.
+#
+# $f = (one or more parameters function)
+# $g = (one or more parameters function)
+#
+# $h = compose($f, $g)
+# $f->($g->($x,$y, ..)) == $h->($x, $y, ..) for any $x, $y, ...
+
+use Modern::Perl;
+
+sub compose {
+    my($f, $g) = @_;
+    return sub { return $f->($g->(@_)); };
+}
+
+sub times3 { return 3*$_[0]; }
+sub times5 { return 5*$_[0]; }
+my $h = compose(\&times3, \&times5);
+say $h->(shift);
diff --git a/challenge-171/paulo-custodio/t/test-1.yaml b/challenge-171/paulo-custodio/t/test-1.yaml
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+++ b/challenge-171/paulo-custodio/t/test-1.yaml
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+- setup:
+  cleanup:
+  args:     20
+  input:
+  output:   12, 18, 20, 24, 30, 36, 40, 42, 48, 54, 56, 60, 66, 70, 72, 78, 80, 84, 88, 90
diff --git a/challenge-171/paulo-custodio/t/test-2.yaml b/challenge-171/paulo-custodio/t/test-2.yaml
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+++ b/challenge-171/paulo-custodio/t/test-2.yaml
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+- setup:
+  cleanup:
+  args:     2
+  input:
+  output:   30