Branches - Farah

lib/reverse_sentence.rb

@@ -1,6 +1,87 @@
 # 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 the string, my_sentence. We iterate through the entire sentence but when a "word" is reached we iterate through that word, swapping each letter.
+# Space complexity: O(1) because nothing new is created, everything is swapped/reversed in place.
+
 def reverse_sentence(my_sentence)
-  raise NotImplementedError
+  if my_sentence == nil
+    return nil
+  end
+
+  # #Take in string and convert to array of words with spaces perseved
+  # sentence_array = my_sentence.split(/\s/)
+
+  # #Iterate through array swapping each words
+  # i = 0
+  # j = sentence_array.length - 1
+  # while i < j
+  #   temp_index = sentence_array[i]
+  #   sentence_array[i] = sentence_array[j]
+  #   sentence_array[j] = temp_index
+
+  #   i += 1
+  #   j -= 1
+  # end
+
+  # #Concatente elements of array into a new string output using (.join)
+  # new_sentence = sentence_array.join(' ')
+
+  # #iterate through new string and replace each character into parameter, my_sentence
+  # new_sentence.length.times do |i|
+  #   my_sentence[i] = new_sentence[i]
+  # end
+
+  # return my_sentence
+
+  ############ Second Try at Problem #############
+
+  # Step 1 - Reverse sentence in its entirity
+  # Create helper method to do this
+  def reverse(string)
+    start_point = 0
+    end_point = string.length - 1
+    while start_point < end_point
+      temp = string[start_point]
+      string[start_point] = string[end_point]
+      string[end_point] = temp
+      start_point += 1
+      end_point -= 1
+    end
+    return string
+  end
+
+  # Pass in my_sentence into Step 1 helper method
+  reverse(my_sentence)
+
+  # Step 2 Identify 'words' in sentence
+  # Identify start and end positions of each word
+  i = 0
+  start_point = 0
+  while i < my_sentence.length
+    if my_sentence[i] == " "
+      end_point = i - 1
+
+      while start_point < end_point
+        temp = my_sentence[start_point]
+        my_sentence[start_point] = my_sentence[end_point]
+        my_sentence[end_point] = temp
+        start_point += 1
+        end_point -= 1
+      end
+      start_point = i + 1
+
+    elsif i == my_sentence.length - 1
+      end_point = i
+      while start_point < end_point
+        temp = my_sentence[start_point]
+        my_sentence[start_point] = my_sentence[end_point]
+        my_sentence[end_point] = temp
+        start_point += 1
+        end_point -= 1
+      end
+
+    end
+    i += 1
+  end
+  return my_sentence
 end

lib/sort_by_length.rb

@@ -1,7 +1,35 @@
 # 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 the array where the array consists of the words in the sentence as the elements of the array.
+# Space complexity: O(n) because a new array is created from the words that make up the sentence string.
 def sort_by_length(my_sentence)
-  raise NotImplementedError, "Method not implemented"
+  if my_sentence.length == nil
+    return []
+  end
+
+  # split string sentence into array (took this from my Exercism assignment)
+  my_sentence = my_sentence.split(/[^\w']+/)
+
+  # iterate through my_sentence array
+  # if word.length at index > word.length at index+1
+  # swap words
+  # else keep words in place
+  # iterate to next word
+  # end
+
+  i = 0
+  while i < (my_sentence.length - 1)
+    j = 0
+    while j < my_sentence.length - i - 1
+      if (my_sentence[j].length) > (my_sentence[j+1]).length
+        temp = my_sentence[j]
+        my_sentence[j] = my_sentence[j+1]
+        my_sentence[j+1] = temp
+      end
+      j += 1
+    end
+    i += 1
+  end
+
+  return my_sentence
 end

test/reverse_sentence_test.rb

@@ -6,16 +6,16 @@
       test_string = "hello, world"
 
       reverse_sentence(test_string)
-
-      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)
 
-      test_string.must_equal "awesome! is Yoda"
+      _(test_string).must_equal "awesome! is Yoda"
     end
   end
 
@@ -27,7 +27,7 @@
 
       reverse_sentence(test_string)
 
-      test_string.must_be_empty
+      _(test_string).must_be_empty
     end
 
     # if the parameter is an object, check for nil
@@ -36,39 +36,39 @@
 
       reverse_sentence(test_string)
 
-      test_string.must_be_nil
+      _(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"
+      _(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"
+      _(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"
+      _(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  "
+      _(test_string).must_equal "     this! do can I  "
     end
   end
 end

test/test_helper.rb

@@ -1,5 +1,6 @@
 require 'minitest/autorun'
 require 'minitest/reporters'
+require 'minitest/skip_dsl'
 require_relative '../lib/reverse_sentence'
 
 Minitest::Reporters.use! Minitest::Reporters::SpecReporter.new