7 files changed, 93 insertions, 5 deletions
diff --git a/challenge-217/sgreen/README.md b/challenge-217/sgreen/README.md
deleted file mode 100644
index 1dceb6430a..0000000000
--- a/challenge-217/sgreen/README.md
+++ /dev/null
@@ -1,3 +0,0 @@
-# The Weekly Challenge 216
-
-Blog: [Letter frequency](https://dev.to/simongreennet/letter-frequency-338m)
diff --git a/challenge-218/sgreen/README.md b/challenge-218/sgreen/README.md
index 1dceb6430a..393dc9b36a 100644
--- a/challenge-218/sgreen/README.md
+++ b/challenge-218/sgreen/README.md
@@ -1,3 +1,3 @@
-# The Weekly Challenge 216
+# The Weekly Challenge 218
 
-Blog: [Letter frequency](https://dev.to/simongreennet/letter-frequency-338m)
+Blog: [The one about maximums](https://dev.to/simongreennet/the-one-about-maximums-40cm)
diff --git a/challenge-218/sgreen/blog.txt b/challenge-218/sgreen/blog.txt
new file mode 100644
index 0000000000..14f46c3e78
--- /dev/null
+++ b/challenge-218/sgreen/blog.txt
@@ -0,0 +1 @@
+https://dev.to/simongreennet/the-one-about-maximums-40cm
+\ No newline at end of file
diff --git a/challenge-218/sgreen/perl/ch-1.pl b/challenge-218/sgreen/perl/ch-1.pl
new file mode 100755
index 0000000000..3139fff84f
--- /dev/null
+++ b/challenge-218/sgreen/perl/ch-1.pl
@@ -0,0 +1,17 @@
+#!/usr/bin/env perl
+
+use strict;
+use warnings;
+use feature 'say';
+use experimental 'signatures';
+
+use List::Util 'max';
+
+sub main (@array) {
+    @array = sort { $a <=> $b } @array;
+    my $solution1 = $array[-3] * $array[-2] * $array[-1];
+    my $solution2 = $array[0] * $array[1] * $array[-1];
+    say max( $solution1, $solution2 );
+}
+
+main(@ARGV);
+\ No newline at end of file
diff --git a/challenge-218/sgreen/perl/ch-2.pl b/challenge-218/sgreen/perl/ch-2.pl
new file mode 100755
index 0000000000..221d712e13
--- /dev/null
+++ b/challenge-218/sgreen/perl/ch-2.pl
@@ -0,0 +1,31 @@
+#!/usr/bin/env perl
+
+use strict;
+use warnings;
+use integer;
+use feature 'say';
+use experimental 'signatures';
+
+use JSON 'decode_json';
+use List::Util qw(max sum);
+
+sub main ($matrix) {
+    my $solution = 0;
+    my $cols     = scalar( @{ $matrix->[0] } );
+    my $xor_row  = 2**$cols - 1;
+
+    # Convert the matrix into a row of integers
+    my @matrix = map { oct( '0b' . join( '', @$_ ) ) } @$matrix;
+
+    foreach my $col_xor ( 0 .. $xor_row ) {
+        my @xor_matrix = map { $_ ^ $col_xor } @matrix;
+        my $total      = sum( map { max( $xor_row - $_, $_ ) } @xor_matrix );
+        if ( $total > $solution ) {
+            $solution = $total;
+        }
+    }
+
+    say $solution;
+}
+
+main( decode_json( $ARGV[0] ) );
+\ No newline at end of file
diff --git a/challenge-218/sgreen/python/ch-1.py b/challenge-218/sgreen/python/ch-1.py
new file mode 100755
index 0000000000..7085e998f4
--- /dev/null
+++ b/challenge-218/sgreen/python/ch-1.py
@@ -0,0 +1,16 @@
+#!/usr/bin/env python
+
+import sys
+
+
+def main(array):
+    array = sorted(array)
+    solution1 = array[-3] * array[-2] * array[-1]
+    solution2 = array[0] * array[1] * array[-1]
+    print(max(solution1, solution2))
+
+
+if __name__ == '__main__':
+    # Turn the strings into integers
+    n = [int(i) for i in sys.argv[1:]]
+    main(n)
diff --git a/challenge-218/sgreen/python/ch-2.py b/challenge-218/sgreen/python/ch-2.py
new file mode 100755
index 0000000000..9ac2a65a8c
--- /dev/null
+++ b/challenge-218/sgreen/python/ch-2.py
@@ -0,0 +1,26 @@
+#!/usr/bin/env python3
+
+import json
+import sys
+from operator import xor
+
+
+def main(matrix):
+    solution = 0
+    cols = len(matrix[0])
+    xor_row = 2 ** cols - 1
+
+    # Convert the matrix into a row of integers
+    matrix = [int(''.join(str(b) for b in x), 2) for x in matrix]
+
+    for col_xor in range(2 ** cols):
+        xor_matrix = [xor(x, col_xor) for x in matrix]
+        total = sum([max(xor_row - x, x) for x in xor_matrix])
+        if total > solution:
+            solution = total
+
+    print(solution)
+
+
+if __name__ == '__main__':
+    main(json.loads(sys.argv[1]))