5kyu: add best travel

Signed-off-by: Matej Focko <mfocko@redhat.com>

5kyu/best_travel/solution.rb

@@ -0,0 +1,24 @@
+def choose_best_sum(t, k, ls)
+  def choose_best_sum_rec(max_total_distance, n, distances)
+    if n == 0 && max_total_distance >= 0 then
+      return 0
+    elsif max_total_distance < 0 || distances.size < 1 then
+      return nil
+    end
+
+    found = Array.new(2)
+
+    travelled = distances.pop
+    including_last = choose_best_sum_rec(max_total_distance - travelled, n - 1, distances)
+    if including_last != nil then
+      found[0] = including_last + travelled
+    end
+
+    found[1] = choose_best_sum_rec(max_total_distance, n, distances)
+    distances.push(travelled)
+
+    return found.select { |x| x != nil }.max
+  end
+
+  choose_best_sum_rec(t, k, ls.sort)
+end

README.md

@@ -113,6 +113,10 @@
 
 - [Esolang Interpreters #2 - Custom Smallfuck Interpreter](https://www.codewars.com/kata/58678d29dbca9a68d80000d7) - [solution](5kyu/esolang_interpreters_ii)
 
+### Ruby
+
+- [Best travel](https://www.codewars.com/kata/55e7280b40e1c4a06d0000aa) - [solution](5kyu/best_travel)
+
 ## 6 kyu
 
 ### Rust