Branches -- Paige D.

lib/reverse_sentence.rb

@@ -1,6 +1,72 @@
 # A method to reverse the words in a sentence, in place.
-# Time complexity: ?
-# Space complexity: ?
+# Time complexity: O(n) - my method does not have any nested loops, but it will run through the length of the original string multiple times
+# Space complexity: O(n) - a second variable (reverse) needs to be created, which will take up as much space as the original string
 def reverse_sentence(my_sentence)
-  raise NotImplementedError
+  if my_sentence != nil
+    # Creates array of words and spaces
+    words_array = words(my_sentence)
+
+    # Revereses the order of the words
+    length = words_array.length
+    i = 0
+    j = length - 1
+    (length / 2).times do
+      # selects word at smallest index that has not been swapped
+      word_1 = words_array[i]
+      # selects words at largest index that has not been swapped
+      word_2 = words_array[j]
+
+      words_array[i] = word_2
+      words_array[j] = word_1
+
+      i += 1
+      j -= 1
+    end
+
+    reverse = words_array.join
+
+    # Overrides original string with order of characters in reverse
+    i = 0
+    my_sentence.length.times do
+      my_sentence[i] = reverse[i]
+      i += 1
+    end
+  end
+
+  return my_sentence
+end
+
+# Helper method to convert sentence into array of words - O(n) time complexity
+def words(my_sentence)
+  length = my_sentence.length
+  words_array = []
+  i = 0
+  word = ""
+
+  until i == length
+    l = my_sentence[i]
+    j = my_sentence[i + 1]
+
+    if l != " " && j != " "
+      word += l
+    elsif l != " " && j == " "
+      word += l
+      words_array << word
+      word = ""
+    elsif l == " " && j == " "
+      word += l
+    elsif l == " " && j != " "
+      word += l
+      words_array << word
+      word = ""
+    end
+
+    if i == length - 1
+      words_array << word
+    end
+
+    i += 1
+  end
+
+  return words_array
 end

lib/sort_by_length.rb

@@ -1,7 +1,21 @@
 # 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"
+  new_sentence = my_sentence.split(" ") 
+  length = new_sentence.length
+  i = 0
+
+  (length - 1).times do
+    j = new_sentence[i]
+    if new_sentence[i].length > new_sentence[i + 1].length
+      new_sentence[i] = new_sentence[i + 1]
+      new_sentence[i + 1] = j
+    end
+
+    i += 1
+  end
+
+  return new_sentence
 end

test/sort_by_length.rb → test/sort_by_length_test.rb

@@ -16,4 +16,4 @@
   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
-end
+end