diff --git a/.DS_Store b/.DS_Store
new file mode 100644
index 0000000..10f4d43
Binary files /dev/null and b/.DS_Store differ
diff --git a/lib/reverse_sentence.rb b/lib/reverse_sentence.rb
index 3fe7cac..6a6a324 100644
--- a/lib/reverse_sentence.rb
+++ b/lib/reverse_sentence.rb
@@ -1,6 +1,27 @@
 # A method to reverse the words in a sentence, in place.
-# Time complexity: ?
-# Space complexity: ?
+# Time complexity: O(n^2) where n is the length of string
+# Space complexity: O(n) where n is the length of string
+
 def reverse_sentence(my_sentence)
-  raise NotImplementedError
-end
+  if my_sentence == nil
+    return nil
+  end
+  
+  char_count = 0
+  position_count = my_sentence.length + 1
+  
+  while char_count < my_sentence.length
+    if my_sentence[0] != " "
+      my_sentence.insert(position_count - 1, my_sentence[0])
+      my_sentence[0] = ""
+      char_count += 1
+    else
+      position_count = my_sentence.length-char_count
+      my_sentence.insert(position_count, " ")
+      my_sentence[0] = ""
+      char_count += 1
+    end
+  end
+  
+  return my_sentence
+end
\ No newline at end of file
diff --git a/lib/sort_by_length.rb b/lib/sort_by_length.rb
index a5713ad..e307349 100644
--- a/lib/sort_by_length.rb
+++ b/lib/sort_by_length.rb
@@ -1,7 +1,22 @@
 # 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) where n is the length of array
+# Space complexity: O(n) where n is length of string/array
 def sort_by_length(my_sentence)
-  raise NotImplementedError, "Method not implemented"
+  # using bubble sort
+  sentence_in_array = my_sentence.split(" ")
+  i = 0
+  while i < sentence_in_array.length-1
+    j = 0
+    while j < sentence_in_array.length-i-1
+      if sentence_in_array[j].length > sentence_in_array[j+1].length
+        temp = sentence_in_array[j]
+        sentence_in_array[j] = sentence_in_array[j+1]
+        sentence_in_array[j+1] = temp
+      end
+      j += 1
+    end
+    i += 1
+  end
+  return sentence_in_array
 end
diff --git a/test/reverse_sentence_test.rb b/test/reverse_sentence_test.rb
index 346069b..02400d2 100644
--- a/test/reverse_sentence_test.rb
+++ b/test/reverse_sentence_test.rb
@@ -4,70 +4,70 @@
   describe "basic tests" do
     it "reverse a sentence with two words" do
       test_string = "hello, world"
-
+      
       reverse_sentence(test_string)
-
+      
       test_string.must_equal "world hello,"
     end
-
+    
     it "reverse a sentence with three words" do
       test_string = "Yoda is awesome!"
-
+      
       reverse_sentence(test_string)
-
+      
       test_string.must_equal "awesome! is Yoda"
     end
   end
-
+  
   # check for edge cases
   describe "edge cases" do
     # if it's a string parameter, check for empty
     it "reverse an empty sentence" do
       test_string = ""
-
+      
       reverse_sentence(test_string)
-
+      
       test_string.must_be_empty
     end
-
+    
     # if the parameter is an object, check for nil
     it "nil object passed to sentence reverse" do
       test_string = nil
-
+      
       reverse_sentence(test_string)
-
+      
       test_string.must_be_nil
     end
-
+    
     it "reverse a sentence with one word" do
       test_string = "world"
-
+      
       reverse_sentence(test_string)
-
+      
       test_string.must_equal "world"
     end
-
+    
     it "reverse a sentence with multiple words" do
       test_string = "I'm a better engineer today than I was yesterday."
-
+      
       reverse_sentence(test_string)
-
+      
       test_string.must_equal "yesterday. was I than today engineer better a I'm"
     end
-
+    
     it "reverse a sentence with multiple spaces between words" do
       test_string = "How  do  you   like     them      apples?"
-
+      
       reverse_sentence(test_string)
-
+      
       test_string.must_equal "apples?      them     like   you  do  How"
     end
-
+    
     it "reverse a sentence with preceeding and trailing white spaces" do
       test_string = "  I can do this!     "
-
+      
       reverse_sentence(test_string)
-
+      
       test_string.must_equal "     this! do can I  "
     end
   end
diff --git a/test/sort_by_length.rb b/test/sort_by_length_test.rb
similarity index 99%
rename from test/sort_by_length.rb
rename to test/sort_by_length_test.rb
index c38d976..1eb292f 100644
--- a/test/sort_by_length.rb
+++ b/test/sort_by_length_test.rb
@@ -8,11 +8,11 @@
   it "will return an array of words, by length" do
     expect(sort_by_length("I love Ada")).must_equal ["I", "Ada", "love"]
   end
-
+  
   it "will return an array of words by length, words that are of equal length will appear in the order they appear" do
     expect(sort_by_length("words of equal length")).must_equal ["of", "words", "equal", "length"]
   end
-
+  
   it "will return an array of words by length, words that are of equal length will appear in the order they appear" do
     expect(sort_by_length("I love great awesome words")).must_equal ["I", "love", "great", "words", "awesome"]
   end