9 files changed, 130 insertions, 8 deletions
diff --git a/challenge-304/sgreen/README.md b/challenge-304/sgreen/README.md
deleted file mode 100644
index 4bb689be34..0000000000
--- a/challenge-304/sgreen/README.md
+++ /dev/null
@@ -1,3 +0,0 @@
-# The Weekly Challenge 303
-
-Blog: [Earn with 3 digits](https://dev.to/simongreennet/earn-with-3-digits-45b6)
diff --git a/challenge-305/sgreen/README.md b/challenge-305/sgreen/README.md
deleted file mode 100644
index 4bb689be34..0000000000
--- a/challenge-305/sgreen/README.md
+++ /dev/null
@@ -1,3 +0,0 @@
-# The Weekly Challenge 303
-
-Blog: [Earn with 3 digits](https://dev.to/simongreennet/earn-with-3-digits-45b6)
diff --git a/challenge-306/sgreen/README.md b/challenge-306/sgreen/README.md
index 4bb689be34..c4195b4620 100644
--- a/challenge-306/sgreen/README.md
+++ b/challenge-306/sgreen/README.md
@@ -1,3 +1,3 @@
-# The Weekly Challenge 303
+# The Weekly Challenge 306
 
-Blog: [Earn with 3 digits](https://dev.to/simongreennet/earn-with-3-digits-45b6)
+Blog: [The last odd](https://dev.to/simongreennet/the-last-odd-kib)
diff --git a/challenge-306/sgreen/blog.txt b/challenge-306/sgreen/blog.txt
new file mode 100644
index 0000000000..dbd3d73b2f
--- /dev/null
+++ b/challenge-306/sgreen/blog.txt
@@ -0,0 +1 @@
+https://dev.to/simongreennet/the-last-odd-kib
+\ No newline at end of file
diff --git a/challenge-306/sgreen/perl/ch-1.pl b/challenge-306/sgreen/perl/ch-1.pl
new file mode 100755
index 0000000000..b90109c70f
--- /dev/null
+++ b/challenge-306/sgreen/perl/ch-1.pl
@@ -0,0 +1,26 @@
+#!/usr/bin/env perl
+
+use strict;
+use warnings;
+use feature 'say';
+use experimental 'signatures';
+
+use List::Util 'sum';
+
+sub main (@ints) {
+    my $solution = 0;
+
+    my $l = scalar(@ints);
+
+    # The odd-length length of sub array
+    for ( my $length = 1 ; $length <= $l ; $length += 2 ) {
+        # The starting position of this sub array
+        foreach my $start ( 0 .. $l - $length ) {
+            $solution += sum( @ints[ $start .. $start + $length - 1 ] );
+        }
+    }
+
+    say $solution;
+}
+
+main(@ARGV);
diff --git a/challenge-306/sgreen/perl/ch-2.pl b/challenge-306/sgreen/perl/ch-2.pl
new file mode 100755
index 0000000000..1f09eea6b2
--- /dev/null
+++ b/challenge-306/sgreen/perl/ch-2.pl
@@ -0,0 +1,25 @@
+#!/usr/bin/env perl
+
+use strict;
+use warnings;
+use feature 'say';
+use experimental 'signatures';
+
+sub main (@ints) {
+    while ( $#ints > 0 ) {
+        # Sort the list, and remove the last two elements
+        @ints = sort { $a <=> $b } @ints;
+        my $x = pop(@ints);
+        my $y = pop(@ints);
+
+        if ( $x != $y ) {
+            # If the last two elements, append the difference to the ints
+            #  array. We know that x is greater than y, always.
+            push @ints, $x - $y;
+        }
+    }
+
+    say $#ints == 0 ? $ints[0] : 0;
+}
+
+main(@ARGV);
diff --git a/challenge-306/sgreen/python/ch-1.py b/challenge-306/sgreen/python/ch-1.py
new file mode 100755
index 0000000000..d4c66cca35
--- /dev/null
+++ b/challenge-306/sgreen/python/ch-1.py
@@ -0,0 +1,28 @@
+#!/usr/bin/env python3
+
+import sys
+
+
+def odd_sum(ints: list) -> int:
+    solution = 0
+
+    l = len(ints)
+
+    # The odd-length length of sub array
+    for length in range(1, l+1, 2):
+        # The starting position of this sub array
+        for start in range(0, l-length+1):
+            solution += sum(ints[start:start+length])
+
+    return solution
+
+
+def main():
+    # Convert input into integers
+    array = [int(n) for n in sys.argv[1:]]
+    result = odd_sum(array)
+    print(result)
+
+
+if __name__ == '__main__':
+    main()
diff --git a/challenge-306/sgreen/python/ch-2.py b/challenge-306/sgreen/python/ch-2.py
new file mode 100755
index 0000000000..9a62b386f6
--- /dev/null
+++ b/challenge-306/sgreen/python/ch-2.py
@@ -0,0 +1,29 @@
+#!/usr/bin/env python3
+
+import sys
+
+
+def last_element(ints: list) -> int:
+    while len(ints) > 1:
+        # Sort the list, and remove the last two elements
+        ints.sort()
+        x = ints.pop()
+        y = ints.pop()
+
+        if x != y:
+            # If the last two elements, append the difference to the ints
+            #  array. We know that x is greater than y, always.
+            ints.append(x-y)
+
+    return ints[0] if ints else 0
+
+
+def main():
+    # Convert input into integers
+    array = [int(n) for n in sys.argv[1:]]
+    result = last_element(array)
+    print(result)
+
+
+if __name__ == '__main__':
+    main()
diff --git a/challenge-306/sgreen/python/test.py b/challenge-306/sgreen/python/test.py
new file mode 100755
index 0000000000..f696c34a47
--- /dev/null
+++ b/challenge-306/sgreen/python/test.py
@@ -0,0 +1,19 @@
+#!/usr/bin/env python3
+
+import unittest
+ch_1 = __import__('ch-1')
+ch_2 = __import__('ch-2')
+
+
+class TestClass(unittest.TestCase):
+    def test_ch_1(self):
+        self.assertEqual(ch_1.odd_sum([2, 5, 3, 6, 4]), 77)
+        self.assertEqual(ch_1.odd_sum([1, 3]), 4)
+
+    def test_ch_2(self):
+        self.assertEqual(ch_2.last_element([3, 8, 5, 2, 9, 2]), 1)
+        self.assertEqual(ch_2.last_element([3, 2, 5]), 0)
+
+
+if __name__ == '__main__':
+    unittest.main()