Space - Stephanie

lib/problems.rb

@@ -1,9 +1,19 @@
 require_relative './stack.rb'
 
-# Time Complexity: ?
-# Space Complexity: ?
+# Time Complexity: O(n)
+# Space Complexity: O(1)
 def balanced(string)
-  raise NotImplementedError, "Not implemented yet"
+  array = string.split("")
+  i = 0 
+  j = -1
+  until i = array.length / 2
+    return false if i != j 
+    i += 1
+    j -+ 1 
+  end
+
+  return true
+
 end
 
 # Time Complexity: ?

lib/queue.rb

@@ -1,28 +1,27 @@
 class Queue
 
   def initialize
-    # @store = ...
-    raise NotImplementedError, "Not yet implemented"
+    @store = LinkedList.new
   end
 
   def enqueue(element)
-    raise NotImplementedError, "Not yet implemented"
+    @store.add_last(element)
   end
 
   def dequeue
-    raise NotImplementedError, "Not yet implemented"
+    @store.remove_first()
   end
 
   def front
-    raise NotImplementedError, "Not yet implemented"
+    #front??
   end
 
   def size
-    raise NotImplementedError, "Not yet implemented"
+    @store.length
   end
 
   def empty?
-    raise NotImplementedError, "Not yet implemented"
+    @store.empty?
   end
 
   def to_s

lib/stack.rb

@@ -1,19 +1,19 @@
 class Stack
   def initialize
-    # @store = ...
-    raise NotImplementedError, "Not yet implemented"
+    @store = LinkedList.new
   end
 
   def push(element)
-    raise NotImplementedError, "Not yet implemented"
+    @store.add_first(element)
   end
 
   def pop
-    raise NotImplementedError, "Not yet implemented"
+    element = @store.remove_first()
+    return element 
   end
 
   def empty?
-    raise NotImplementedError, "Not yet implemented"
+    @store.empty?
   end
 
   def to_s

test/test_helper.rb

@@ -10,4 +10,4 @@
 require_relative "../lib/queue.rb"
 require_relative "../lib/stack.rb"
 # Extra exercises
-# require_relative "../lib/problems.rb"
+require_relative "../lib/problems.rb"