Elle

lib/problems.rb

@@ -1,9 +1,68 @@
 require_relative './stack.rb'
 
 def balanced(string)
-  raise NotImplementedError, "Not implemented yet"
+
+  brackets = {
+    '{'=> '}',
+    '('=> ')',
+    '['=> ']'
+    };
+
+  return true if string.length == 0
+  return false if string.length % 2 != 0
+
+  stack = Stack.new
+
+  string.each_char do |char|
+    if brackets[char]
+      stack.push(char)
+    else
+      return false if char != brackets[stack.pop]
+    end
+  end
+
+  return stack.empty?
+
 end
 
+
+# def balanced(string)?
+
+  # return !stack.empty?
+
+  # stack_left = Stack.new
+  # stack_right = Stack.new
+  # sub_string_length = string.length / 2
+  # left_counter = 0
+  # right_counter = string.length - 1
+  #
+  # until left_counter == sub_string_length
+  #   stack_left.push(string[left_counter])
+  #   left_counter += 1
+  # end
+  #
+  # until right_counter == sub_string_length - 1
+  #   stack_right.push(string[right_counter])
+  #   right_counter -= 1
+  # end
+  #
+  # until stack_left.empty? || stack_right.empty?
+  #   left_value = stack_left.pop
+  #   right_value = stack_right.pop
+  #   return false if left_value != right_value
+  # end
+  #
+  # return true if stack_left.empty? && stack_right.empty?
+
+# end
+
+# def is_even_length?(string)
+#   return (string.length % 2 == 0) ? true : false
+# end
+
+
+
+# OPTIONAL WAVE 4
 def evaluate_postfix(postfix_expression)
   raise NotImplementedError, "Not implemented yet"
-end
+end

lib/queue.rb

@@ -1,31 +1,68 @@
+QUEUE_SIZE = 16
+
 class Queue
 
   def initialize
-    # @store = ...
-    raise NotImplementedError, "Not yet implemented"
+      @store = Array.new(QUEUE_SIZE)
+      @front = nil
+      @rear = nil
+      # setting these to nil because in Ruby -1 also represents the end of the array
   end
 
   def enqueue(element)
-    raise NotImplementedError, "Not yet implemented"
+    if @front == nil
+      @front = 0
+      @rear = 1
+      @store[@front] = element
+    elsif @front == @rear
+      raise Error, "The queue is full."
+    else
+      @store[@rear] = element
+      @rear = (@rear + 1) % QUEUE_SIZE
+    end
   end
 
   def dequeue
-    raise NotImplementedError, "Not yet implemented"
-  end
+    remove_item = @store[@front]
 
-  def front
-    raise NotImplementedError, "Not yet implemented"
-  end
+    raise Error, "The queue is empty." if empty?
 
-  def size
-    raise NotImplementedError, "Not yet implemented"
+    @store[@front] = nil
+    @front = (@front + 1) % QUEUE_SIZE
+
+    return remove_item
   end
 
+  # def front
+  #   raise NotImplementedError, "Not yet implemented"
+  # end
+
+  # def size
+  #   raise NotImplementedError, "Not yet implemented"
+  # end
+
   def empty?
-    raise NotImplementedError, "Not yet implemented"
+    return (@front == nil && @rear == nil) || (@front == @rear)
   end
 
+
+# def to_s
+#   @store.to_s
+# end
+
   def to_s
-    return @store.to_s
+    array_as_string = "["
+    if @store[@front]
+      array_as_string = array_as_string + "#{@store[@front]}"
+    end
+
+    i = @front + 1
+    until i == @rear
+      array_as_string = array_as_string + ", #{@store[i]}"
+      i += 1
+    end
+
+    array_as_string = array_as_string + "]"
+    return array_as_string
   end
 end

lib/stack.rb

@@ -1,19 +1,20 @@
+require_relative 'linked_list.rb'
+
 class Stack
   def initialize
-    # @store = ...
-    raise NotImplementedError, "Not yet implemented"
+    @store = LinkedList.new
   end
 
   def push(element)
-    raise NotImplementedError, "Not yet implemented"
+    @store.add_last(element)
   end
 
   def pop
-    raise NotImplementedError, "Not yet implemented"
+    @store.remove_last
   end
 
   def empty?
-    raise NotImplementedError, "Not yet implemented"
+    @store.empty?
   end
 
   def to_s

test/problems_test.rb

@@ -1,46 +1,42 @@
 require 'minitest/autorun'
 require 'minitest/reporters'
 require_relative '../lib/problems'
-
+require 'minitest/skip_dsl'
 Minitest::Reporters.use! Minitest::Reporters::SpecReporter.new
 
 describe "Test wave 3 problems" do
   describe "balanced" do
     it "Given balanced strings it should return true" do
-      skip
       expect(balanced('(({}))')).must_equal true
     end
 
     it "regards an empty string as balanced" do
-      skip
       expect(balanced('')).must_equal true
     end
 
     it "will return false for an unbalanced set of parens" do
-      skip
       expect(balanced('(()')).must_equal false
       expect(balanced('(()}')).must_equal false
       expect(balanced('([]]')).must_equal false
     end
 
     it "also works for {} and []" do
-      skip
       expect(balanced('[]')).must_equal true
       expect(balanced('{}')).must_equal true
     end
   end
 
-  describe "postfix" do
+  xdescribe "postfix" do
     it "can add a 2 numbers together" do
-      skip
+
       expect(evaluate_postfix("34+")).must_equal 7
       expect(evaluate_postfix("34*")).must_equal 12
       expect(evaluate_postfix("34-")).must_equal -1
       expect(evaluate_postfix("34/")).must_equal 0
     end
 
     it "can add a evaluate a more complicated expression" do
-      skip
+
       expect(evaluate_postfix("34+2*")).must_equal 14
       expect(evaluate_postfix("34*2/")).must_equal 6
       expect(evaluate_postfix("34-1+")).must_equal 0
@@ -49,4 +45,4 @@
       expect(evaluate_postfix("62/5+")).must_equal 8
     end
   end
-end
+end

test/queue_test.rb

@@ -1,7 +1,7 @@
 require 'minitest/autorun'
 require 'minitest/reporters'
 require_relative '../lib/queue'
-
+require 'minitest/skip_dsl'
 Minitest::Reporters.use! Minitest::Reporters::SpecReporter.new
 
 describe "Test Queue Implementation" do
@@ -11,14 +11,12 @@
   end
 
   it "adds something to an empty Queue" do
-    skip
     q = Queue.new
     q.enqueue(10)
     q.to_s.must_equal "[10]"
   end
 
   it "adds multiple somethings to a Queue" do
-    skip
     q = Queue.new
     q.enqueue(10)
     q.enqueue(20)
@@ -27,13 +25,11 @@
   end
 
   it "starts the size of a Queue at 0" do
-    skip
     q = Queue.new
     q.empty?.must_equal true
   end
 
   it "removes something from the Queue" do
-    skip
     q = Queue.new
     q.enqueue(5)
     removed = q.dequeue
@@ -42,7 +38,6 @@
   end
 
   it "removes the right something (LIFO)" do
-    skip
     q = Queue.new
     q.enqueue(5)
     q.enqueue(3)
@@ -53,7 +48,7 @@
   end
 
   it "properly adjusts the size with enqueueing and dequeueing" do
-    skip
+
     q = Queue.new
     q.empty?.must_equal true
     q.enqueue(-1)
@@ -65,12 +60,12 @@
   end
 
   it "returns the front element in the Queue" do
-    skip
+
     q = Queue.new
     q.enqueue(40)
     q.enqueue(22)
     q.enqueue(3)
     q.dequeue
     expect(q.dequeue).must_equal 22
   end
-end
+end

test/stack_test.rb

@@ -1,6 +1,7 @@
 require 'minitest/autorun'
 require 'minitest/reporters'
 require_relative '../lib/stack'
+require 'minitest/skip_dsl'
 Minitest::Reporters.use! Minitest::Reporters::SpecReporter.new
 
 describe "Test Stack Implementation" do
@@ -10,14 +11,12 @@
   end
 
   it "pushes something onto a empty Stack" do
-    skip
     s = Stack.new
     s.push(10)
     s.to_s.must_equal "[10]"
   end
 
   it "pushes multiple somethings onto a Stack" do
-    skip
     s = Stack.new
     s.push(10)
     s.push(20)
@@ -26,13 +25,11 @@
   end
 
   it "starts the stack empty" do
-    skip
     s = Stack.new
     s.empty?.must_equal true
   end
 
   it "removes something from the stack" do
-    skip
     s = Stack.new
     s.push(5)
     removed = s.pop
@@ -41,7 +38,6 @@
   end
 
   it "removes the right something (LIFO)" do
-    skip
     s = Stack.new
     s.push(5)
     s.push(3)
@@ -50,4 +46,4 @@
     removed.must_equal 7
     s.to_s.must_equal "[5, 3]"
   end
-end
+end