Laura | Nodes

lib/reverse_sentence.rb

@@ -1,4 +1,46 @@
-# A method to reverse the words in a sentence, in place.
+# A method to reverse the my_sentences in a sentence, in place.
+# Time: O(n^2)
+# Space: O(1)
 def reverse_sentence(my_sentence)
-  raise NotImplementedError
+
+  if my_sentence == nil || my_sentence == "" || my_sentence.length == 1
+     return my_sentence
+  end
+  reverse_string(0, my_sentence.length - 1, my_sentence)
+  i = 0
+  s = 0
+  e = 0
+
+    while i < my_sentence.length
+      # skip space
+      while my_sentence[i + 1] == " " || my_sentence[i] == " "
+        i += 1
+      end
+      # define start of sentence
+      if my_sentence[i] != " "
+        s = i
+      end
+
+      # find end
+      # why does it go into an infinite loop with OR
+      while my_sentence[i+1] != " " && my_sentence[i+1] != nil
+        i += 1
+      end
+
+      e = i
+      reverse_string(s, e, my_sentence)
+      i += 1
+    end
+end
+
+def reverse_string(startw, endw, string)
+  i = startw
+  j = endw
+  while i < j
+    temp = string[i]
+    string[i] = string[j]
+    string[j] = temp
+    i += 1
+    j -= 1
+  end
 end