diff --git a/Gemfile b/Gemfile
index 46677aa..16ca0b3 100644
--- a/Gemfile
+++ b/Gemfile
@@ -1,6 +1,6 @@
 source 'http://rubygems.org'
 
-ruby '2.5.1'
+ruby '2.5.5'
 
 gem 'rake'
 
diff --git a/Gemfile.lock b/Gemfile.lock
new file mode 100644
index 0000000..c1e2af5
--- /dev/null
+++ b/Gemfile.lock
@@ -0,0 +1,30 @@
+GEM
+  remote: http://rubygems.org/
+  specs:
+    ansi (1.5.0)
+    builder (3.2.3)
+    minitest (5.12.0)
+    minitest-reporters (1.3.8)
+      ansi
+      builder
+      minitest (>= 5.0)
+      ruby-progressbar
+    minitest-skip (0.0.1)
+      minitest (~> 5.0)
+    rake (12.3.3)
+    ruby-progressbar (1.10.1)
+
+PLATFORMS
+  ruby
+
+DEPENDENCIES
+  minitest
+  minitest-reporters
+  minitest-skip
+  rake
+
+RUBY VERSION
+   ruby 2.5.5p157
+
+BUNDLED WITH
+   2.0.2
diff --git a/lib/reverse_sentence.rb b/lib/reverse_sentence.rb
index 3fe7cac..7c92119 100644
--- a/lib/reverse_sentence.rb
+++ b/lib/reverse_sentence.rb
@@ -1,6 +1,37 @@
+def reverse_sentence_from_start_to_end(my_sentence, start_index, end_index)
+  half_width = (end_index - start_index) / 2
+  count = (half_width + 1).to_i
+  count.times do |i|
+    temp = my_sentence[start_index + i]
+    my_sentence[start_index + i] = my_sentence[end_index - i] 
+    my_sentence[end_index - i] = temp
+  end
+end
+
 # A method to reverse the words in a sentence, in place.
-# Time complexity: ?
-# Space complexity: ?
+# Time complexity: O(n**2)
+# Space complexity: O(1)
 def reverse_sentence(my_sentence)
-  raise NotImplementedError
+  if my_sentence.nil?
+    return
+  end
+
+  reverse_sentence_from_start_to_end(my_sentence, 0, my_sentence.length - 1)
+
+  start_index = nil
+  my_sentence.each_char.with_index do |letter, index|
+    if letter != " " && start_index.nil?
+      start_index = index
+    elsif letter == " " && !start_index.nil?
+      end_index = index - 1
+      reverse_sentence_from_start_to_end(my_sentence, start_index, end_index)
+      start_index = nil
+    end
+  end
+
+  if !start_index.nil?
+    reverse_sentence_from_start_to_end(my_sentence, start_index, my_sentence.length - 1)
+  end
 end
+
+reverse_sentence("Yoda  is   awesome")
diff --git a/lib/sort_by_length.rb b/lib/sort_by_length.rb
index a5713ad..8c132e2 100644
--- a/lib/sort_by_length.rb
+++ b/lib/sort_by_length.rb
@@ -1,7 +1,24 @@
 # A method which will return an array of the words in the string
 #  sorted by the length of the word.
-# Time complexity: ?
-# Space complexity: ?
+# Time complexity: O(n**2)
+# Space complexity: O(n)
 def sort_by_length(my_sentence)
-  raise NotImplementedError, "Method not implemented"
-end
+  words = my_sentence.split(" ")
+  results = []
+  words.each do |word|
+    if results.length > 0
+      results.each_with_index do |result, index|
+        if word.length < result.length
+          results.insert(index, word)
+          break
+        elsif index == (results.length - 1)
+          results << word
+          break
+        end
+      end
+    else
+      results << word
+    end
+  end 
+  return results
+end 
diff --git a/test/sort_by_length.rb b/test/sort_by_length_test.rb
similarity index 100%
rename from test/sort_by_length.rb
rename to test/sort_by_length_test.rb