Merge pull request #5698 from mattneleigh/pwc153

	new file:   challenge-153/mattneleigh/perl/ch-1.pl

2 files changed, 139 insertions, 0 deletions

diff --git a/challenge-153/mattneleigh/perl/ch-1.pl b/challenge-153/mattneleigh/perl/ch-1.pl
new file mode 100755
index 0000000000..f2b3f20e91
--- /dev/null
+++ b/challenge-153/mattneleigh/perl/ch-1.pl
@@ -0,0 +1,64 @@
+#!/usr/bin/perl
+
+use strict;
+use warnings;
+use English;
+
+################################################################################
+# Begin main execution
+################################################################################
+
+my $n = 10;
+
+printf(
+    "\nThe first %d Left Factorials are:\n    %s\n\n",
+    $n,
+    join(", ", n_left_factorials($n))
+);
+
+exit(0);
+################################################################################
+# End main execution; subroutines follow
+################################################################################
+
+
+
+################################################################################
+# Calculate the first N Left Factorials (See OEIS A003422)
+# Takes one argument:
+# * A positive integer indicating how many Left Factorials to calculate
+# Returns on success:
+# * A list of the first N Left Factorials
+# Returns on error:
+# * undef if N is not a positive integer
+################################################################################
+sub n_left_factorials{
+    my $n = int(shift());
+
+    return(undef)
+        unless($n > 0);
+
+    my $i;
+    my $factorial;
+    my @left_factorials;
+
+    # Initial setup
+    push(@left_factorials, 1);
+    $factorial = 1;
+
+    for $i (1 .. ($n - 1)){
+        # Multiply our running product by $i, then
+        # store its sum with the previous sum
+        $factorial *= $i;
+        push(
+            @left_factorials,
+            $left_factorials[$#left_factorials] + $factorial
+        );
+    }
+
+    return(@left_factorials);
+
+}
+
+
+
diff --git a/challenge-153/mattneleigh/perl/ch-2.pl b/challenge-153/mattneleigh/perl/ch-2.pl
new file mode 100755
index 0000000000..9e71c1f72f
--- /dev/null
+++ b/challenge-153/mattneleigh/perl/ch-2.pl
@@ -0,0 +1,75 @@
+#!/usr/bin/perl
+
+use strict;
+use warnings;
+use English;
+
+# Need this for state variables
+use v5.10;
+
+################################################################################
+# Begin main execution
+################################################################################
+
+my @numbers = (
+    145,
+    125
+);
+my $number;
+
+foreach $number (@numbers){
+    printf("\nInput: \$n = %d\nOutput: %d\n\n",
+        $number,
+        is_factorion($number)
+    );
+}
+
+exit(0);
+################################################################################
+# End main execution; subroutines follow
+################################################################################
+
+
+
+################################################################################
+# Determine whether a number N is a Factorion (it is equal to the sum of its
+# digits' factorials)
+# Takes one argument:
+# * The number N to examine
+# Returns on success:
+# * 1 if N is a Factorion
+# * 0 if N is not a Factorion
+# Returns on error:
+# * undef if N is less than zero
+################################################################################
+sub is_factorion{
+    my $n = int(shift());
+
+    return(undef)
+        if($n < 0);
+
+    state @factorials;
+    my $sum = 0;
+
+    unless(@factorials){
+        # Factorial list wasn't defined... generate
+        # it; this only happens the first time this
+        # function is called
+        push(@factorials, 1);
+        for(1 .. 9){
+            push(@factorials, $factorials[$#factorials] * $ARG);
+        }
+    }
+
+    # Split the number into digits and add up
+    # the factorials of each digit
+    foreach(split('', $n)){
+        $sum += $factorials[$ARG];
+    }
+    
+    return($sum == $n);
+
+}
+
+
+