diff --git a/lib/problems.rb b/lib/problems.rb index 61bcaa5a..7d2ea904 100644 --- a/lib/problems.rb +++ b/lib/problems.rb @@ -1,7 +1,27 @@ require_relative './stack.rb' def balanced(string) - raise NotImplementedError, "Not implemented yet" + bracket_buds = { + '(' => ')', + '[' => ']', + '{' => '}' + } + + stack = Stack.new + list = string.split('') + + if list.length % 2 != 0 + return false + end + + list.each do |char| + if bracket_buds.include?(char) + stack.push(char) + elsif char != bracket_buds[stack.pop] + return false + end + end + return true end def evaluate_postfix(postfix_expression) diff --git a/lib/queue.rb b/lib/queue.rb index 828217c6..d3d70e33 100644 --- a/lib/queue.rb +++ b/lib/queue.rb @@ -1,31 +1,64 @@ class Queue + QUEUE_SIZE = 20 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" + if @front == -1 + @front = 0 + @rear = 1 + @store[@front] = element + elsif @front == @rear + raise Error, "Queue is full" + else # not empty, not full + @store[@rear] = element + @rear = (@rear + 1) % QUEUE_SIZE + end end def dequeue - raise NotImplementedError, "Not yet implemented" + if @front == -1 + raise Error, "Queue is empty" + else + dequeued = @store[@front] + @front = (@front + 1) % QUEUE_SIZE + if @front == @rear + @front = @rear = -1 + end + return dequeued + end end def front - raise NotImplementedError, "Not yet implemented" + if @front.empty? + raise Error, "There is no front! There is no rear! Queue is empty" + else + return @store[@front] + end end def size - raise NotImplementedError, "Not yet implemented" + return @store[@front..@rear].length end def empty? - raise NotImplementedError, "Not yet implemented" + if @front == -1 + return true + else + return false + end end def to_s - return @store.to_s + elements_in_queue = [] + i = @front + while i < @rear + elements_in_queue << @store[i] + i = (i + 1) % QUEUE_SIZE + end + return elements_in_queue.to_s end end diff --git a/lib/stack.rb b/lib/stack.rb index cfc6ef0f..d6d47802 100644 --- a/lib/stack.rb +++ b/lib/stack.rb @@ -1,19 +1,22 @@ +require_relative 'linked_list' + 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" + if @stack == nil + return true + end end def to_s diff --git a/test/problems_test.rb b/test/problems_test.rb index f851f1d2..ca6d0dfb 100644 --- a/test/problems_test.rb +++ b/test/problems_test.rb @@ -7,37 +7,37 @@ 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 @@ -45,7 +45,7 @@ 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 diff --git a/test/queue_test.rb b/test/queue_test.rb index 9b616a30..eb6b9309 100644 --- a/test/queue_test.rb +++ b/test/queue_test.rb @@ -11,14 +11,14 @@ 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 +27,13 @@ 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 +42,7 @@ end it "removes the right something (LIFO)" do - skip + q = Queue.new q.enqueue(5) q.enqueue(3) @@ -53,7 +53,7 @@ end it "properly adjusts the size with enqueueing and dequeueing" do - skip + q = Queue.new q.empty?.must_equal true q.enqueue(-1) @@ -65,7 +65,7 @@ end it "returns the front element in the Queue" do - skip + q = Queue.new q.enqueue(40) q.enqueue(22) diff --git a/test/stack_test.rb b/test/stack_test.rb index df5046c8..a790a3d0 100644 --- a/test/stack_test.rb +++ b/test/stack_test.rb @@ -10,14 +10,14 @@ 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 +26,13 @@ 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 +41,7 @@ end it "removes the right something (LIFO)" do - skip + s = Stack.new s.push(5) s.push(3)