Fix requires

Author: Dbz

algorithms/sort_stack.rb

@@ -3,7 +3,7 @@
 # an additional temporary stack, but you may not copy the elements into any other data structure
 # (such as an array). The stack supports the following operations: push, pop, peek, and isEmpty.
 
-class Stack
+class SortStack
   attr_reader :size
 
   def initialize
@@ -36,7 +36,7 @@ def empty?
   def sort
     return self if empty?
 
-    temp = Stack.new
+    temp = SortStack.new
     temp.push pop
 
     until empty?

data-structures/queue_using_two_stacks.rb

@@ -1,7 +1,7 @@
 # CtCI 6th Edition Problem 3.4
 # Queue via Stacks: Implement a MyQueue class which implements a queue using two stacks.
 
-class Stack
+class MyStack
   attr_reader :size
 
   def initialize
@@ -15,15 +15,16 @@ def push(el)
   end
 
   def pop
+    return if @size.zero?
     @size -= 1
     @stack.pop
   end
 end
 
 class MyQueue
   def initialize
-    @push_stack = Stack.new
-    @pop_stack  = Stack.new
+    @push_stack = MyStack.new
+    @pop_stack  = MyStack.new
   end
 
   def add(item)

spec/algorithms/sort_stack_spec.rb

@@ -1,8 +1,8 @@
-require_relative '../../algorithms/sort_stack'
+require './algorithms/sort_stack'
 
 describe 'Stack#sort' do
-  it 'sorts elements of a stack so that the smallest elements on on top' do
-    stack = Stack.new
+  it 'sorts elements of a stack so that the smallest elements is on top' do
+    stack = SortStack.new
     first_ten = (0..9).to_a
     first_ten.each { |n| stack.push n }
     sorted_stack = stack.sort

spec/data-structures/queue_using_two_stacks_spec.rb

@@ -1,4 +1,4 @@
-require_relative '../../data-structures/queue_using_two_stacks'
+require './data-structures/queue_using_two_stacks'
 
 describe 'Queue using two stacks' do
   it 'adds items and removes them in the order they were added (FIFO)' do