Sockets - Karla

lib/problems.rb

@@ -1,9 +1,43 @@
 require_relative './stack.rb'
 
 def balanced(string)
-  raise NotImplementedError, "Not implemented yet"
+  bracket_hash = 
+  {
+    ")" => "(",
+    "]" => "[",
+    "}" => "{"
+  }
+
+  bracket_stack = Stack.new
+
+  string.each_char do |char|
+    if bracket_hash.values.include?(char)
+      bracket_stack.push(char)
+    elsif bracket_hash.keys.include?(char)
+      if bracket_stack.empty? || bracket_hash[char] != bracket_stack.pop()
+        return false
+      end
+    end
+  end
+  return bracket_stack.empty?
 end
 
 def evaluate_postfix(postfix_expression)
-  raise NotImplementedError, "Not implemented yet"
+  operators = ["+", "-", "*", "/"]
+  stack = Stack.new
+
+  postfix_expression.each_char do |char|
+    if char =~ /\d/
+      stack.push(char)
+      puts "char #{char}"
+    elsif operators.include?(char)
+      second = stack.pop().to_i
+      first = stack.pop().to_i
+      result = first.public_send(char, second)
+      puts char
+      puts "result #{result}"
+      stack.push(result)
+    end
+  end
+  return stack.pop()
 end

lib/queue.rb

@@ -1,31 +1,60 @@
 class Queue
 
+  QUEUE_SIZE = 10
+
   def initialize
-    # @store = ...
-    raise NotImplementedError, "Not yet implemented"
+    @store = Array.new(QUEUE_SIZE)
+    @front = @rear = -1
   end
 
   def enqueue(element)
-    raise NotImplementedError, "Not yet implemented"
-  end
+    if @front == -1 # Q is empty
+      @rear = 1
+      @front = 0
+      @store[@front] = element
+    elsif @front == @rear
+      raise Error, "Q Full"
+    else # not empty
+      new_rear = (@rear + 1) % QUEUE_SIZE
+      @store[@rear] = element
+      @rear = new_rear
+    end
+  end	 
 
   def dequeue
-    raise NotImplementedError, "Not yet implemented"
+    if @front == -1 && @rear == -1 # Q is empty
+      raise Error, "Q Empty"
+    elsif @store[@front +1] == nil # Q has one item and becomes empty
+      removed = @store[@front]
+      @store[@front] = nil
+      @front = -1
+      @rear = -1
+      return removed
+    else
+      removed = @store[@front]
+      @store[@front] = nil
+      @front = @front + 1
+      return removed
+    end
   end
 
   def front
-    raise NotImplementedError, "Not yet implemented"
+    return @front
   end
 
   def size
-    raise NotImplementedError, "Not yet implemented"
+    return @store.length
   end
 
   def empty?
-    raise NotImplementedError, "Not yet implemented"
+    if @front == -1 && @rear == -1
+      return true
+    else
+      return false
+    end
   end
 
   def to_s
-    return @store.to_s
+    return @store[@front...@rear].to_s
   end
 end

lib/stack.rb

@@ -1,22 +1,23 @@
+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"
+    return @store.empty?()
   end
 
   def to_s
     return @store.to_s
   end
-end
+end

test/problems_test.rb

@@ -7,45 +7,38 @@
 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
 
     it "also works if the string has opens and closes in the beginning and end" do
-      skip
       expect(balanced('[]()')).must_equal true
     end
   end
 
   describe "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

test/queue_test.rb

@@ -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 +48,6 @@
   end
 
   it "properly adjusts the size with enqueueing and dequeueing" do
-    skip
     q = Queue.new
     q.empty?.must_equal true
     q.enqueue(-1)
@@ -65,7 +59,6 @@
   end
 
   it "returns the front element in the Queue" do
-    skip
     q = Queue.new
     q.enqueue(40)
     q.enqueue(22)

test/stack_test.rb

@@ -10,14 +10,12 @@
   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 +24,11 @@
   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 +37,6 @@
   end
 
   it "removes the right something (LIFO)" do
-    skip
     s = Stack.new
     s.push(5)
     s.push(3)