Merge pull request #23 from ailbhe-tweedie/atweedie

Solutions for week 1 & 2

5 files changed, 132 insertions, 0 deletions

diff --git a/challenge-001/ailbhe-tweedie/README b/challenge-001/ailbhe-tweedie/README
new file mode 100644
index 0000000000..36d4034b70
--- /dev/null
+++ b/challenge-001/ailbhe-tweedie/README
@@ -0,0 +1 @@
+Solution by Ailbhe Tweedie
diff --git a/challenge-001/ailbhe-tweedie/perl5/ch-1.pl b/challenge-001/ailbhe-tweedie/perl5/ch-1.pl
new file mode 100755
index 0000000000..22c1d97107
--- /dev/null
+++ b/challenge-001/ailbhe-tweedie/perl5/ch-1.pl
@@ -0,0 +1,14 @@
+#!/usr/bin/perl
+#
+# Write a script to replace the character ‘e’ with ‘E’ in the string
+# ‘Perl Weekly Challenge’. Also print the number of times the
+# character ‘e’ is found in the string.
+
+my $string = 'Perl Weekly Challenge';
+my $numberOfEs;
+while ($string =~ /\G[^e]*e/g) {
+	$numberOfEs++;
+}
+print "Es: $numberOfEs\n";
+my $replaced = $string =~ s/e/E/g;
+print "replaced: $replaced";
diff --git a/challenge-002/ailbhe-tweedie/README b/challenge-002/ailbhe-tweedie/README
new file mode 100644
index 0000000000..36d4034b70
--- /dev/null
+++ b/challenge-002/ailbhe-tweedie/README
@@ -0,0 +1 @@
+Solution by Ailbhe Tweedie
diff --git a/challenge-002/ailbhe-tweedie/perl5/ch-1.pl b/challenge-002/ailbhe-tweedie/perl5/ch-1.pl
new file mode 100755
index 0000000000..e4a72a65e9
--- /dev/null
+++ b/challenge-002/ailbhe-tweedie/perl5/ch-1.pl
@@ -0,0 +1,9 @@
+#!/usr/bin/env perl
+#
+# Solution to challenge #1 of the Perl Weekly Challenge 002.
+
+while (<>) {
+	chomp;
+	$_ =~ s/^0+//;
+	print "$_\n";
+}
diff --git a/challenge-002/ailbhe-tweedie/perl5/ch-2.pl b/challenge-002/ailbhe-tweedie/perl5/ch-2.pl
new file mode 100755
index 0000000000..84d904ee09
--- /dev/null
+++ b/challenge-002/ailbhe-tweedie/perl5/ch-2.pl
@@ -0,0 +1,107 @@
+#!/usr/bin/env perl
+#
+# Solution to challenge #2 of the Perl Weekly Challenge 002.
+#
+# Task: Write a script that can convert integers to and from a base35
+# representation, using the characters 0-9 and A-Y. 
+#
+# Prerequisites: cpan install Scalar::Util::Numeric
+#
+# Usage:
+# > echo {0.999} | ./ch-02.pl to
+#
+# Test with:
+# >  echo {0..99} | ./ch-02.pl to | awk '{print $3}' | ./ch-02.pl from
+#
+# TODO: add tests
+
+use strict;
+use warnings;
+use Scalar::Util::Numeric qw(isint);
+use Data::Dump;
+
+use v5.10;
+
+# TODO: split the string right here into an array and don't keep the $BASE variable
+my $BASE = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXY";
+
+exit 1 unless @ARGV == 1;
+my $switch = $ARGV[0];
+
+while (<STDIN>) {
+	chomp;
+	# TODO: find out how to stream input, instead of saving it to an array first
+	my @input = split;
+	for my $i (@input) {
+		my $output;
+		if ($switch eq "to") {
+			$output = toBase35($i);
+		} elsif ($switch eq "from") {
+			$output = fromBase35($i);
+		} else {
+			say "Please specify to/from";
+			exit 2;
+		}
+		# `pretty' print output
+		printf "%-4s\t==>\t%-4s\n", $i, $output;
+	}
+}
+exit 0;
+
+sub toBase35 {
+	my $input = shift;
+
+	my @base = split "", $BASE;
+	my @convert;
+	my $max = 0;
+
+	# Figure out the highest power of the base we need by incrementing
+	# base^power until it is bigger than the input. The exponent we're
+	# looking for is 1 less.
+	while (1) {
+		last unless @base ** ++$max <= $input;
+	}
+
+	# Figure out the number's place values in a similar way by subtracting
+	# base^power from the input until the input is smaller than the value
+	# we're subtracting from it. The place values are saved in the array @convert.
+	while ($max > 0) {
+		my $exp = $max - 1;
+		my $pow = @base ** $exp;
+		my $place;
+		while ($pow <= $input) {
+			$input -= $pow;
+			$place++;
+		}
+		push @convert, $place;
+		$max--;
+	}
+
+	# Return our number in the new base, by indexing the @base array with
+	# the @convert array.
+	# TODO: figure out if this implict return is `bad style'
+	my $output = join "", @base[@convert];
+}
+
+sub fromBase35 {
+	my $input = shift;
+
+	# We create a hash converting an alphanumeric character in the new base to
+	# a base10 value
+	# TODO: move this out of the function
+	my %hash;
+	my @base = split "", $BASE;
+	for my $i (0..@base-1) {
+		$hash{$base[$i]} = $i;
+	}
+
+	my @based = split "", $input; # bad variable name
+	my $max = @based - 1;
+	my $output;
+	# TODO: A for loop would probably be more clear at this point.
+	while ($max >= 0) {
+		$output += ( @base ** $max ) * $hash{@based[@based - $max - 1]};
+		$max--;
+	}
+	return $output;
+}