imported solution to first task, sorry no time to do second (and didn't much like the question anyway:-))

2 files changed, 146 insertions, 26 deletions

diff --git a/challenge-062/duncan-c-white/README b/challenge-062/duncan-c-white/README
index 0551c0a85d..736cbb1087 100644
--- a/challenge-062/duncan-c-white/README
+++ b/challenge-062/duncan-c-white/README
@@ -1,41 +1,43 @@
-Task 1: "Product SubArray
+Task 1: "Sort Email Addresses
 
-Given a list of 4 or more numbers, write a script to find the contiguous
-sublist that has the maximum product. The length of the sublist is
-irrelevant; your job is to maximize the product.
+Write a script that takes a list of email addresses (one per line) and sorts them first by the domain part of the email address, and then by the part to the left of the @ (known as the mailbox).
 
-Example
-
-Input: [ 2, 5, -1, 3 ]
-
-Output: [ 2, 5 ] which gives maximum product 10.
-"
+Note that the domain is case-insensitive, while the mailbox part is case sensitive. (Some email providers choose to ignore case, but that’s another matter entirely.)
 
-My notes: very straightforward.
+If your script is invoked with arguments, it should treat them as file names and read them in order, otherwise your script should read email addresses from standard input.
+Bonus
 
+Add a -u option which only includes unique email addresses in the output, just like sort -u.
+Example
 
-Task 2: "IPv4 Partition
+If given the following list:
 
-You are given a string containing only digits (0..9). The string should
-have between 4 and 12 digits.
+name@example.org
+rjt@cpan.org
+Name@example.org
+rjt@CPAN.org
+user@alpha.example.org
 
-Write a script to print every possible valid IPv4 address that can be
-made by partitioning the input string.
+Your script (without -u) would return:
 
-For the purpose of this challenge, a valid IPv4 address consists of four
-'octets' i.e. A, B, C and D, separated by dots (.).
+user@alpha.example.org
+rjt@cpan.org
+rjt@CPAN.org
+Name@example.org
+name@example.org
 
-Each octet must be between 0 and 255, and must not have any leading
-zeroes. (e.g., 0 is OK, but 01 is not.)
+With -u, the script would return:
 
-Example
+user@alpha.example.org
+rjt@CPAN.org
+Name@example.org
+name@example.org
+"
 
-Input: 25525511135,
+My notes: cool question. Will have a go!
 
-Output:
 
-255.255.11.135
-255.255.111.35
+Task 2: "N Queens - in 3D..
 "
 
-My notes: sounds quite straightforward, nice problem.
+My notes: sorry, I'm rather busy, sounds like a horrible problem, not doing it.
diff --git a/challenge-062/duncan-c-white/perl/ch-1.pl b/challenge-062/duncan-c-white/perl/ch-1.pl
new file mode 100755
index 0000000000..031d7a9386
--- /dev/null
+++ b/challenge-062/duncan-c-white/perl/ch-1.pl
@@ -0,0 +1,118 @@
+#!/usr/bin/perl
+#
+# Task 1: "Sort Email Addresses
+#
+# Write a script that takes a list of email addresses (one per line)
+# and sorts them first by the domain part of the email address, and then
+# by the part to the left of the @ (known as the mailbox).
+# 
+# Note that the domain is case-insensitive, while the mailbox part is case
+# sensitive. (Some email providers choose to ignore case, but that's
+# another matter entirely.)
+# 
+# If your script is invoked with arguments, it should treat them as file
+# names and read them in order, otherwise your script should read email
+# addresses from standard input.
+# 
+# Bonus
+# 
+# Add a -u option which only includes unique email addresses in the output,
+# just like sort -u.
+# 
+# Example
+# 
+# If given the following list:
+# 
+# name@example.org
+# rjt@cpan.org
+# Name@example.org
+# rjt@CPAN.org
+# user@alpha.example.org
+# 
+# Your script (without -u) would return:
+# 
+# user@alpha.example.org
+# rjt@cpan.org
+# rjt@CPAN.org
+# Name@example.org
+# name@example.org
+# 
+# With -u, the script would return:
+# 
+# user@alpha.example.org
+# rjt@CPAN.org
+# Name@example.org
+# name@example.org
+# "
+# 
+# My notes: cool question. Will have a go!  I also added '-i' meaning:
+# treat the mailname part as case-insensitive as well.  Running this
+# script on the above input with -i and -u outputs only:
+# 
+# user@alpha.example.org
+# rjt@CPAN.org
+# name@example.org
+# 
+
+use strict;
+use warnings;
+use feature 'say';
+use Function::Parameters;
+use Getopt::Long;
+
+my $unique = 0;
+my $caseinsensitive = 0;
+my $result = GetOptions( "u" => \$unique, "i" => \$caseinsensitive );
+
+die "Usage: sort-email-addresses [-u] [-i] (addresses on input)\n"
+	unless $result;
+
+my @addr;
+while( <> )
+{
+	chomp;
+	s/\s+//g;
+	die "bad input $_\n" unless /@/;
+	push @addr, $_;
+}
+
+sub compare
+{
+	my( $aname, $adom ) = split( /@/, $a, 2 );
+	my( $bname, $bdom ) = split( /@/, $b, 2 );
+
+	# compare domains first, case insensitively
+	$adom = lc($adom);
+	$bdom = lc($bdom);
+	return $adom cmp $bdom if $adom ne $bdom;
+
+	# now compare names, case insensitively if $caseinsensitive
+	if( $caseinsensitive )
+	{
+		$aname = lc($aname);
+		$bname = lc($bname);
+	}
+	return $aname cmp $bname;
+}
+
+#
+# my $out = sanitize( $in );
+#	Sanitize the email address $in, giving $out.
+#	Sanitizing means:
+#	- lowercasing every domain, because domains are case insensitive
+#	- lowercasing every name IF $caseinsensitive
+#
+fun sanitize( $in )
+{
+	my( $name, $dom ) = split( /@/, $in, 2 );
+	$dom = lc($dom);
+	$name = lc($name) if $caseinsensitive;
+	return $name.'@'.$dom;
+}
+
+
+my %seen;
+@addr = grep { ! $seen{sanitize($_)}++ } @addr if $unique;
+@addr = sort compare @addr;
+
+say for @addr;