diff --git a/lib/reverse_sentence.rb b/lib/reverse_sentence.rb
index 3fe7cac..e8a424c 100644
--- a/lib/reverse_sentence.rb
+++ b/lib/reverse_sentence.rb
@@ -1,6 +1,31 @@
+#require "pry"
 # A method to reverse the words in a sentence, in place.
-# Time complexity: ?
-# Space complexity: ?
+# Time complexity: o(n)
+# Space complexity: o(1)
 def reverse_sentence(my_sentence)
-  raise NotImplementedError
+  #raise NotImplementedError
+  if my_sentence == nil 
+    return my_sentence
+  end
+  words = my_sentence.split() 
+  i = 0
+  j = words.length - 1
+  
+  while i < j do 
+    temp = words[i]
+    # binding.pry
+    words[i] = words[j]
+    words[j] = temp
+    # binding.pry
+    i += 1
+    j -= 1
+  end 
+  # binding.pry
+  # print words
+   final_word = words.join(" ")
+  return final_word
 end
+
+
+
+
diff --git a/lib/sort_by_length.rb b/lib/sort_by_length.rb
index a5713ad..2380dfd 100644
--- a/lib/sort_by_length.rb
+++ b/lib/sort_by_length.rb
@@ -1,7 +1,19 @@
 # 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(1)
 def sort_by_length(my_sentence)
-  raise NotImplementedError, "Method not implemented"
+  #raise NotImplementedError, "Method not implemented"
+  new_sentence = my_sentence.split()
+  n = new_sentence.length
+  for j in 0..n-1
+    for i in 0..n-2-j
+      if new_sentence[i].length > new_sentence[i + 1].length
+        temp = new_sentence[i]
+        new_sentence[i] = new_sentence[i+1]
+        new_sentence[i + 1] = temp
+      end
+    end
+  end
+  return new_sentence
 end
diff --git a/test/reverse_sentence_test.rb b/test/reverse_sentence_test.rb
index 346069b..49c5d79 100644
--- a/test/reverse_sentence_test.rb
+++ b/test/reverse_sentence_test.rb
@@ -5,70 +5,78 @@
     it "reverse a sentence with two words" do
       test_string = "hello, world"
 
-      reverse_sentence(test_string)
+      # reverse_sentence(test_string)
+      reverse_sentence(test_string).must_equal "world hello,"
 
-      test_string.must_equal "world hello,"
+      # test_string.must_equal "world hello,"
     end
 
     it "reverse a sentence with three words" do
       test_string = "Yoda is awesome!"
 
-      reverse_sentence(test_string)
+      #reverse_sentence(test_string)
 
-      test_string.must_equal "awesome! is Yoda"
+      #test_string.must_equal "awesome! is Yoda"
+      reverse_sentence(test_string).must_equal "awesome! is Yoda"
     end
   end
 
-  # check for edge cases
+  #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
+      #reverse_sentence(test_string)
+      #test_string.must_be_empty
+      reverse_sentence(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)
+      #reverse_sentence(test_string)
 
-      test_string.must_be_nil
+      #test_string.must_be_nil
+       reverse_sentence(test_string).must_be_nil
+      
     end
 
     it "reverse a sentence with one word" do
       test_string = "world"
 
-      reverse_sentence(test_string)
+      #reverse_sentence(test_string)
 
-      test_string.must_equal "world"
+      #test_string.must_equal "world"
+      reverse_sentence(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)
+      #reverse_sentence(test_string)
 
-      test_string.must_equal "yesterday. was I than today engineer better a I'm"
+      #test_string.must_equal "yesterday. was I than today engineer better a I'm"
+      reverse_sentence(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)
+      #reverse_sentence(test_string)
 
-      test_string.must_equal "apples?      them     like   you  do  How"
+      #test_string.must_equal "apples?      them     like   you  do  How"
+      reverse_sentence(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)
+      #reverse_sentence(test_string)
 
-      test_string.must_equal "     this! do can I  "
+      #test_string.must_equal "     this! do can I  "
+      reverse_sentence(test_string).must_equal "     this! do can I  "
     end
   end
 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