Merge pull request #5546 from mattneleigh/pwc148

	new file:   challenge-148/mattneleigh/perl/ch-1.pl

2 files changed, 174 insertions, 0 deletions

diff --git a/challenge-148/mattneleigh/perl/ch-1.pl b/challenge-148/mattneleigh/perl/ch-1.pl
new file mode 100755
index 0000000000..d3bea6ecc2
--- /dev/null
+++ b/challenge-148/mattneleigh/perl/ch-1.pl
@@ -0,0 +1,44 @@
+#!/usr/bin/perl
+
+use strict;
+use warnings;
+use English;
+
+################################################################################
+# Begin main execution
+################################################################################
+
+# Tens-place and ones-place numbers that do
+# not have an 'e' in them; numbers from
+# sixty six to one hundred all have an 'e'
+# so just use a limited subset of digits
+my @tens = ( 0, 3, 4, 5, 6 );
+my @ones = ( 0, 2, 4, 6 );
+my @ebans;
+my $tens_digit;
+my $ones_digit;
+
+# Loop over the tens place digits
+foreach $tens_digit (@tens){
+    # Loop over the ones place digits
+    foreach $ones_digit (@ones){
+        if($tens_digit){
+            # Tens digit is not zero...
+            push(@ebans, $tens_digit . $ones_digit);
+        } else{
+            # Tens digit is zero...
+            push(@ebans, $ones_digit) if($ones_digit);
+        }
+    }
+}
+
+print("\nThe Eban numbers below 100 are:\n");
+print(join(", ", @ebans), "\n\n");
+
+exit(0);
+################################################################################
+# End main execution; subroutines follow
+################################################################################
+
+
+
diff --git a/challenge-148/mattneleigh/perl/ch-2.pl b/challenge-148/mattneleigh/perl/ch-2.pl
new file mode 100755
index 0000000000..36baaa45bd
--- /dev/null
+++ b/challenge-148/mattneleigh/perl/ch-2.pl
@@ -0,0 +1,130 @@
+#!/usr/bin/perl
+
+use strict;
+use warnings;
+use English;
+
+################################################################################
+# Begin main execution
+################################################################################
+
+my $count = 5;
+my @cardanos;
+
+@cardanos = calculate_first_cardano_triplets($count);
+
+printf("\nThe first %d Cardano Triplets are:\n", scalar(@cardanos));
+foreach(@cardanos){
+    printf("  (%s)\n", join(", ", @{$_}));
+}
+print("\n");
+
+
+exit(0);
+################################################################################
+# End main execution; subroutines follow
+################################################################################
+
+
+
+################################################################################
+# Find a specified number of the first Cardano Triplets, numbers (A, B, C) that
+# meet specified parameters (see link below)
+# Takes two arguments:
+# * The number of Triplets to find; if this number is zero (0), ALL Cardano
+#   Triplets whose members' sum is less than or equal to the maximum sum value
+#   (see below) will be found; if there aren't that many triplets within the
+#   search range, the returned list (see farther below) will be shorter than
+#   specified but will contain all Triplets within the range
+# * The maximum sum of A, B, and C up to which we'll search for Triplets; if
+#   this argument is omitted or is false a default of 1000 will be used
+# Returns:
+# * A list of refs to the Cardano Triplets found, e.g.:
+#   (
+#       [ 2, 1, 5 ],
+#       [ 5, 1, 52 ],
+#       [ 5, 2, 13 ],
+#       ...
+#   )
+# NOTES: Cardano Triplets are described here:
+# https://projecteuler.net/problem=251
+# Which particular triplets you get will depend on the value of the maximum
+# sum.
+################################################################################
+sub calculate_first_cardano_triplets{
+    my $count = int(shift());
+    my $max = shift();
+
+    my @cardanos = ();
+    my $a;
+    my $b;
+    my $c;
+
+    if(defined($max) && $max){
+        $max = int($max);
+    } else{
+        $max = 1000;
+    }
+
+    # Traditionally this is done with the
+    # variables adding up to some
+    # particular maximum value...
+    for($a=1; $a<=($max - 2); $a++){
+        for($b=1; $b<=($max - $a - 1); $b++){
+            for($c=1; $c<=($max - $a - $b); $c++){
+                my $b_sqrt_c = $b * sqrt($c);
+
+                # The calculated value should be zero
+                # if we have a Cardano Triplet, but it
+                # could be slightly off because of
+                # round-off error
+                if(
+                    abs(cbrt($a + $b_sqrt_c) + cbrt($a - $b_sqrt_c) - 1)
+                    <
+                    0.000000001
+                ){
+                    # We have a Cardano Triplet
+                    push(@cardanos, [ $a, $b, $c ]);
+
+                    # Break out of all loops if there's a
+                    # count defined and we've hit it
+                    $max = 0
+                        if($count && (scalar(@cardanos) == $count));
+                }
+
+            }
+        }
+    }
+
+    return(@cardanos);
+
+}
+
+
+
+################################################################################
+# Compute the cube root of a number
+# Takes one argument:
+# * The number whose cube root is desired
+# Returns:
+# * The cube root
+################################################################################
+sub cbrt{
+    my $x = shift();
+
+    if($x < 0){
+
+        # $x is negative; play some sign games
+        return(-((-$x) ** (1 / 3)));
+
+    } else{
+
+        # $x is positive; very straightforward
+        return($x ** (1 / 3));
+
+    }
+
+}
+
+
+