diff --git a/.DS_Store b/.DS_Store
new file mode 100644
index 0000000..e7f3a15
Binary files /dev/null and b/.DS_Store differ
diff --git a/lib/reverse_sentence.rb b/lib/reverse_sentence.rb
index 3fe7cac..13a9761 100644
--- a/lib/reverse_sentence.rb
+++ b/lib/reverse_sentence.rb
@@ -1,6 +1,52 @@
-# A method to reverse the words in a sentence, in place.
-# Time complexity: ?
-# Space complexity: ?
+# A method to reverse the words in a sentence, in place.	
+# Time complexity: O(n^3)	
+# Space complexity: O(1)
 def reverse_sentence(my_sentence)
-  raise NotImplementedError
+  if my_sentence == nil
+    return nil
+  end
+  my_sentence = string_reverse(my_sentence)
+  my_sentence = word_reverse(my_sentence)
+  return my_sentence
+end
+
+def string_reverse(string)
+  i = 0
+  j = string.length - 1
+  temp_i = ""
+  temp_j = ""
+  while i < j do
+    temp_i = string[i]
+    temp_j = string[j]
+    string[i] = temp_j
+    string[j] = temp_i
+    i+=1
+    j-=1
+  end
+  return string
+end
+
+def word_reverse(string)
+  i = 0
+  j = 0
+  length = string.length
+  while i < length
+    while string[j] != " " && j < length do
+      j += 1
+    end
+    j -= 1
+    word_start = i
+    word_end = j
+    while word_start < word_end do
+      temp_i = string[word_start]
+      temp_j = string[word_end]
+      string[word_start] = temp_j
+      string[word_end] = temp_i
+      word_start+=1
+      word_end-=1
+    end
+    i = j+2
+    j = i
+  end
+  return string
 end
diff --git a/lib/sort_by_length.rb b/lib/sort_by_length.rb
index a5713ad..e0fc8e2 100644
--- a/lib/sort_by_length.rb
+++ b/lib/sort_by_length.rb
@@ -1,7 +1,26 @@
 # 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: On
+
 def sort_by_length(my_sentence)
-  raise NotImplementedError, "Method not implemented"
+  sorted_sentence = my_sentence.split(" ")
+  bubble_sort(sorted_sentence, sorted_sentence.length)
+  return sorted_sentence
 end
+
+def bubble_sort(array, length)
+  i = 0
+  while i < length-1 # outer loop
+    j = 0
+    while j < length-i-1 # inner loop
+      if array[j].length > array[j+1].length # swap
+        temp = array[j]
+        array[j] = array[j+1]
+        array[j+1] = temp
+      end
+      j += 1
+    end
+    i += 1
+  end
+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