Merge pull request #7112 from simongreen-net/master

Simon's solution to challenge 191

6 files changed, 108 insertions, 2 deletions

diff --git a/challenge-191/sgreen/README.md b/challenge-191/sgreen/README.md
index d9610d7312..ef0288441e 100644
--- a/challenge-191/sgreen/README.md
+++ b/challenge-191/sgreen/README.md
@@ -1,3 +1,3 @@
-# The Weekly Challenge 190
+# The Weekly Challenge 191
 
-Blog [Capital letters decoded!](https://dev.to/simongreennet/capital-letters-decoded-315f)
+Blog [The cute recursive function](https://dev.to/simongreennet/the-cute-recursive-function-2gdo)
diff --git a/challenge-191/sgreen/blog.txt b/challenge-191/sgreen/blog.txt
new file mode 100644
index 0000000000..933290931a
--- /dev/null
+++ b/challenge-191/sgreen/blog.txt
@@ -0,0 +1 @@
+https://dev.to/simongreennet/the-cute-recursive-function-2gdo
\ No newline at end of file
diff --git a/challenge-191/sgreen/perl/ch-1.pl b/challenge-191/sgreen/perl/ch-1.pl
new file mode 100755
index 0000000000..387ebbf45b
--- /dev/null
+++ b/challenge-191/sgreen/perl/ch-1.pl
@@ -0,0 +1,15 @@
+#!/usr/bin/env perl
+
+use strict;
+use warnings;
+use feature 'say';
+use experimental 'signatures';
+
+sub main (@nums) {
+    # Sort the list numerically
+    @nums = sort { $a <=> $b } @nums;
+
+    say $nums[-1] >+ 2 * $nums[-2] ? 1 : -1;
+}
+
+main(@ARGV);
diff --git a/challenge-191/sgreen/perl/ch-2.pl b/challenge-191/sgreen/perl/ch-2.pl
new file mode 100755
index 0000000000..69e9686bea
--- /dev/null
+++ b/challenge-191/sgreen/perl/ch-2.pl
@@ -0,0 +1,43 @@
+#!/usr/bin/env perl
+
+use strict;
+use warnings;
+use feature 'say';
+use experimental 'signatures';
+
+use List::Util 'none';
+
+sub find_solutions ( $front, $back ) {
+    # Recursive function to find possible solutions. Front is the numbers we
+    #  have processed, back is what remains
+    if ( scalar(@$back) == 0 ) {
+        return 1;
+    }
+
+    # Iterate over the next value
+    my $count = 0;
+
+    foreach my $i ( @{ $back->[0] } ) {
+        # Call the recursive function if we haven't used this number already
+        if ( none { $_ == $i } @$front ) {
+            $count +=
+              find_solutions( [ @$front, $i ], [ @{$back}[ 1 .. $#$back ] ] );
+        }
+    }
+
+    # Return the number of matches up the recursive function
+    return $count;
+}
+
+sub main ($n) {
+    # Generate a list of list with a possible value for each number
+    my @possible = ();
+
+    foreach my $i ( 1 .. $n ) {
+        push @possible, [ grep { $_ % $i == 0 or $i % $_ == 0 } ( 1 .. $n ) ];
+    }
+
+    say find_solutions( [], \@possible );
+}
+
+main( $ARGV[0] )
diff --git a/challenge-191/sgreen/python/ch-1.py b/challenge-191/sgreen/python/ch-1.py
new file mode 100755
index 0000000000..f121df2fba
--- /dev/null
+++ b/challenge-191/sgreen/python/ch-1.py
@@ -0,0 +1,15 @@
+#!/usr/bin/env python3
+
+import sys
+
+
+def main(s):
+    # Sort the list numerically
+    nums = [int(x) for x in s]
+    nums.sort()
+
+    print(1 if nums[-1] >= 2 * nums[-2] else -1)
+
+
+if __name__ == '__main__':
+    main(sys.argv[1:])
diff --git a/challenge-191/sgreen/python/ch-2.py b/challenge-191/sgreen/python/ch-2.py
new file mode 100755
index 0000000000..6c610e6d88
--- /dev/null
+++ b/challenge-191/sgreen/python/ch-2.py
@@ -0,0 +1,32 @@
+#!/usr/bin/env python3
+
+import sys
+
+def find_solutions(front, back):
+    '''Recursive function to find possible solutions. Front is the numbers we
+       have processed, back is what remains'''
+    if len(back) == 0:
+        return 1
+
+    # Iterate over the next value
+    count = 0
+    for i in back[0]:
+        # Call the recursive function if we haven't used this number already
+        if i not in front:
+            count += find_solutions([*front, i], back[1:])
+
+    # Return the number of matches up the recursive function
+    return count
+
+def main(n):
+    '''Main function'''
+    # Generate a list of list with a possible value for each number
+    possible = []
+    for i in range(1, n+1):
+        possible.append([j for j in range(1, n+1) if j % i == 0 or i % j == 0])
+
+    print(find_solutions([], possible))
+
+
+if __name__ == '__main__':
+    main(int(sys.argv[1]))