Space - Jessica

lib/problems.rb

@@ -3,7 +3,32 @@
 # Time Complexity: ?
 # Space Complexity: ?
 def balanced(string)
-  raise NotImplementedError, "Not implemented yet"
+  array = string.split('')
+  return false if array.length % 2 != 0
+
+  stack = Stack.new
+  array.each do |ele|
+    stack.push(ele)
+  end
+
+  array.length.times do |i|
+    remove = stack.pop
+    case remove
+    when '['
+      return false if array[i] != ']'
+    when ']'
+      return false if array[i] != '['
+    when '{'
+      return false if array[i] != '}'
+    when '}'
+      return false if array[i] != '{'
+    when '('
+      return false if array[i] != ')'
+    when ')'
+      return false if array[i] != '('
+    end
+  end
+  return true
 end
 
 # Time Complexity: ?

lib/queue.rb

@@ -1,31 +1,66 @@
 class Queue
 
   def initialize
-    # @store = ...
-    raise NotImplementedError, "Not yet implemented"
+    @store = []
+    @max_size = 20
+    @front = -1
+    @rear = -1
   end
 
   def enqueue(element)
-    raise NotImplementedError, "Not yet implemented"
+    if (@front == 0 && @rear == (@max_size - 1)) || 
+        (@rear == ((@front - 1) % (@max_size - 1)))
+          raise "No more space"
+    elsif @front == -1 # Queue is empty
+      # initialize front and rear
+      @front += 1
+      @rear += 1
+    elsif (@rear == (@max_size - 1) && @front != 0) # rear needs to wrap around
+      @rear = 0
+    else
+      @rear += 1
+    end
+    @store[@rear] = element
   end
 
   def dequeue
-    raise NotImplementedError, "Not yet implemented"
+    if @front == -1 
+      raise "Nothing to remove"
+    elsif @front == @rear
+      dequeue = front
+      @front = -1
+      @rear = -1
+    else
+      dequeue = front
+      @front += 1
+    end
+    return dequeue
   end
 
   def front
-    raise NotImplementedError, "Not yet implemented"
+    return @store[@front] if @front != -1 
   end
 
+  # get how many elements are in the array
   def size
-    raise NotImplementedError, "Not yet implemented"
+    if @rear >= @front
+      return (@rear - @front) + 1
+    else
+      return (@max_size) - (@front - @rear) + 1
+    end
   end
 
   def empty?
-    raise NotImplementedError, "Not yet implemented"
+    return @front == -1
   end
 
   def to_s
-    return @store.to_s
+    if @front <= @rear
+      return @store[@front, @max_size].to_s
+    else
+      arr = @store[@front, @max_size]
+      arr += @store[0.. @rear]
+      return arr.to_s
+    end
   end
 end

lib/stack.rb

@@ -1,19 +1,18 @@
 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"
+    @store.remove_first
   end
 
   def empty?
-    raise NotImplementedError, "Not yet implemented"
+    @store.empty?
   end
 
   def to_s

test/problems_test.rb

@@ -2,7 +2,7 @@
 
 Minitest::Reporters.use! Minitest::Reporters::SpecReporter.new
 
-xdescribe "Test wave 3 problems" do
+describe "Test wave 3 problems" do
   describe "balanced" do
     it "Given balanced strings it should return true" do
 
@@ -26,7 +26,7 @@
       expect(balanced('[]')).must_equal true
       expect(balanced('{}')).must_equal true
     end
-
+    
     it "also works if the string has opens and closes in the beginning and end" do
 
       expect(balanced('[]()')).must_equal true

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"