- Added solutions by Javier Luque.

2 files changed, 228 insertions, 0 deletions

diff --git a/challenge-062/javier-luque/perl/ch-1.pl b/challenge-062/javier-luque/perl/ch-1.pl
new file mode 100644
index 0000000000..a5cfe59990
--- /dev/null
+++ b/challenge-062/javier-luque/perl/ch-1.pl
@@ -0,0 +1,53 @@
+#!/usr/bin/perl
+# Test: ./ch-1.pl -u
+use strict;
+use warnings;
+use feature qw /say/;
+use Getopt::Long;
+
+# Unique flag
+my $unique;
+GetOptions ("unique"  => \$unique);
+
+# Hash to store unique emails
+my %unique_emails;
+
+# Data
+my @data = qw /
+    name@example.org
+    rjt@cpan.org
+    Name@example.org
+    rjt@CPAN.org
+    user@alpha.example.org
+/;
+
+my @sorted_data = sort by_domain @data;
+@sorted_data = grep { make_unique($_) } @sorted_data
+    if ($unique);
+say join "\n", @sorted_data;
+
+# Check if the email is unique
+sub make_unique {
+    my $email = shift;
+    my ($user, $domain) = split_email($email);
+    my $unique_email = $user . '@' . lc($domain);
+
+    return 0
+    	if ($unique_emails{$unique_email});
+
+    $unique_emails{$unique_email} = 1;
+    return 1;
+}
+
+# Sort by domain function
+sub by_domain {
+    my ($user_a, $domain_a) = split ('\@', $::a);
+    my ($user_b, $domain_b) = split ('\@', $::b);
+    lc($domain_a) cmp lc($domain_b) or
+    $user_a       cmp $user_b;
+}
+
+# Split email into username and domain
+sub split_email {
+    return split ('\@', shift);
+}
diff --git a/challenge-062/javier-luque/perl/ch-2.pl b/challenge-062/javier-luque/perl/ch-2.pl
new file mode 100644
index 0000000000..aedfe1e3db
--- /dev/null
+++ b/challenge-062/javier-luque/perl/ch-2.pl
@@ -0,0 +1,175 @@
+#!/usr/bin/perl
+# Test: ./ch-2.pl
+use strict;
+use warnings;
+use feature qw /say/;
+
+# Size of board
+my $size = $ARGV[0] || 6;
+
+# Store best solution
+our $bs_board       = init_board( $size );
+our $bs_queen_count = 0;
+
+# Our Playing board
+my $board = init_board( $size );
+if (nqueens($board, 0, 0, 0)) {
+    say "Real Solution:\n";
+    say display_board($board);
+} else {
+    say "Best Solution:\n";
+    say display_board($bs_board);
+}
+
+# Nqueens algorithm
+sub nqueens {
+    my ($board, $next_z, $next_col, $placed) = @_;
+    my $size = scalar(@$board);
+    my $index = $next_z * $size + $next_col;
+
+    # We found a solution
+    return 1
+    	if $index > ($size * $size) - 1 ;
+
+    # We've moved to the next level
+    if ($next_col > $size - 1) {
+    	$next_z++;
+    	$next_col -= $size;
+    };
+
+    # Backtrack till we find a solution
+    for my $row (0 .. $size - 1) {
+    	if (valid_placement($board, $size, $next_z, $row, $next_col)) {
+    		$board->[$next_z]->[$row]->[$next_col] = 1;
+
+    		# Queen placed
+    		$placed++;
+
+    		# Current best solution
+    		if ($bs_queen_count < $placed) {
+    			copy_board($board, $bs_board);
+    			$bs_queen_count = $placed;
+    		}
+
+    		# Solution found
+    		return 1
+    			if (nqueens($board, $next_z, $next_col + 1, $placed));
+
+    		# Backtrack
+    		$placed--;
+    		$board->[$next_z]->[$row]->[$next_col] = 0;
+    	}
+    }
+
+    # If we get here there is no
+    # possible solution to this chain
+    return 0;
+}
+
+# Check valid placements
+sub valid_placement {
+    my ($board, $size, $height, $row, $col) = @_;
+
+    # Check rows
+    for (my $i = 0; $i < $col; $i++) {
+    	return 0
+    		if ($board->[$height]->[$row]->[$i]);
+    }
+
+    # Check 2d upper left diagonals
+    my $i = $row; my $j = $col;
+    while ($i >= 0 && $j >= 0) {
+    	return 0
+    		if ($board->[$height]->[$i]->[$j]);
+    	$i--; $j--;
+    }
+
+    # Check 2d lower right
+    $i = $row; $j = $col;
+    while ($i <= $size && $j >= 0) {
+    	return 0
+    		if ($board->[$height]->[$i]->[$j]);
+    	$i++; $j--;
+    }
+
+    # Check lower z
+    for (my $k = $height - 1; $k >= 0; $k--) {
+    	my $range = $height - $k;
+
+    	for my $i (-$range, 0, $range) {
+    		for my $j (-$range, 0, $range) {
+    			my $a = $row + $i ;
+    			my $b = $col + $j;
+
+    			# Out of bound;
+    			next if ($a < 0 || $b < 0);
+    			next if ($a >= $size || $b >= $size);
+
+    			return 0
+    				if ($board->[$k]->[$a]->[$b]);
+    		}
+    	}
+    }
+
+
+    # Return true if we don't
+    # collide with another queen
+    return 1;
+}
+
+# Initializes the board
+sub init_board {
+    my $size = (shift) - 1;
+    my @board;
+
+    for my $i (0 .. $size) {
+    	for my $j (0 .. $size) {
+    		for my $k (0 .. $size) {
+    			$board[$i][$j][$k] = 0;
+    		}
+    	}
+    }
+
+    return \@board;
+}
+
+# Displays the board
+sub display_board {
+    my $board = shift;
+    my $size = scalar (@$board);
+
+    # Store the board string into $b
+    my $b;
+    for my $k (0 .. $size - 1) {
+    	$b .= "z = $k\n";
+    	$b .= '|' . '-' x (4 * $size - 1) . '|' . "\n";
+    	for my $i (0 .. $size - 1) {
+    		$b .= '|';
+    		for my $j (0 .. $size - 1) {
+    			my $space = ($board->[$k]->[$i]->[$j] == 1) ?
+    			            '*' : ' ';
+    			$b .= " $space |"
+    		}
+    		$b .= "\n";
+    	}
+    	$b .= '|' . '-' x (4 * $size - 1) . '|' . "\n\n";
+    }
+
+    # Return the board representation
+    return $b;
+}
+
+# Copy board
+sub copy_board {
+    my ($src, $copy) = @_;
+    my $size = scalar(@$src) - 1;
+
+    for my $i (0 .. $size) {
+    	for my $j (0 .. $size) {
+    		for my $k (0 .. $size) {
+    			$copy->[$i]->[$j]->[$k] =
+    				$src->[$i]->[$j]->[$k];
+    		}
+    	}
+    }
+}