Edit Stacks and Queues guide

stacks_queues/stacks_queues.md

@@ -1,49 +1,48 @@
 ## Introduction
 
-Stacks and queues are foundational data structures that are useful when adding and removing in particular orders. It's important to be comfortable with these two data structures.
+Stacks and queues are foundational data structures that are useful for problems that rely on adding and removing elements in a particular order. It's important to be comfortable with these two data structures.
 
 ## Stacks
-A **stack** is a data structure that stores objects in which the most recently stored objects are the first ones to be removed, (LIFO: last in, first out). An example to help you remember the mechanics of a stack is to associate it with stacks in real life. With a stack of plates, the plates that are placed on top of a stack will be the first ones that are removed from the top!
+A **stack** stores objects such that the most recently added objects are the first ones to be removed (LIFO: last in, first out). An example to help you remember the mechanics of a stack is to associate it with stacks in real life. In a stack of plates, the ones placed on top will be the first ones removed!
 
 ![](https://i.imgur.com/qMSmxsa.png)
 
 It's important to know the common operations of a stack. The two key stack operations are:
-1) pop(): removing an item from the stack in a last in, first out order (LIFO)
-2) push(item): adding an item to the stack
+1. pop(): removing an item from the stack in last in, first out order (LIFO)
+2. push(item): adding an item (to the top of the stack)
 
 
 ## Queues
-A **queue** is a data structure that stores objects in which the most stored objects are the first ones to be removed. A helpful acronym associated with queues is FIFO, first in first out. An example to help you remember the mechanics of a queue is to associate it with queues in real life. With a queue of people waiting to get a seat in a restaurant, the first people to get in the queue will be the first people seated at that restaurant.
+A **queue** stores objects such that the objects added earliest are the first ones to be removed (FIFO: first in first out). An example to help you remember the mechanics of a queue is to associate it with queues in real life. In a queue of people waiting to get a seat in a restaurant, the first people in line (in the queue) will be the first to get a table.
 
 ![](https://i.imgur.com/NKuZd0s.png)
 
 It's important to know the common operations associated with a queue. The two important queue operations are:
-1) dequeue(): removing an item from the queue in a first in, first out order (FIFO)
-2) enqueue(item): adding an item to the queue
+1. dequeue(): removing an item from the queue in first in, first out order (FIFO)
+2. enqueue(item): adding an item (to the back of the queue)
 
 ## Key takeaways
-* Stacks are very useful for it's backtracking features. For example, parsing questions tend to use stacks because of the LIFO property.
+* Stacks are very useful for their backtracking features. For example, parsing questions tend to use stacks because of their LIFO property.
 * Stacks can be used to implement recursive solutions iteratively.
-* Queues are useful when the ordering of the data matters as it preserves that ordering. For example, they're used for caching.
+* Queues are useful when the ordering of the data matters because they preserve the original ordering. For example, queues are used for caching.
 
 ## Example problems
-* Stacks: 
+* Stacks:
   * [Implement a queue with stacks](https://leetcode.com/problems/implement-queue-using-stacks/description/)
 
 * Queues:
   * [LRU Cache](https://leetcode.com/problems/lru-cache/)
 
 ## Resources
 ### Guides
-* [Overview of stacks & queues with applications](https://www.cs.cmu.edu/~adamchik/15-121/lectures/Stacks%20and%20Queues/Stacks%20and%20Queues.html)
-* [In depth stacks guide](https://medium.com/basecs/stacks-and-overflows-dbcf7854dc67)
-* [In depth queues guide](https://medium.com/basecs/to-queue-or-not-to-queue-2653bcde5b04)
+* [Overview of stacks and queues with applications](https://www.cs.cmu.edu/~adamchik/15-121/lectures/Stacks%20and%20Queues/Stacks%20and%20Queues.html)
+* [In-depth stacks guide](https://medium.com/basecs/stacks-and-overflows-dbcf7854dc67)
+* [In-depth queues guide](https://medium.com/basecs/to-queue-or-not-to-queue-2653bcde5b04)
 
 ### Libraries
-* [Java queue library](https://docs.oracle.com/javase/7/docs/api/java/util/Queue.html)
-* [Java stack library](
+* [Java Queue library](https://docs.oracle.com/javase/7/docs/api/java/util/Queue.html)
+* [Java Stack library](
 https://docs.oracle.com/javase/7/docs/api/java/util/Stack.html)
 * [Python queue library](
 https://docs.python.org/2/tutorial/datastructures.html#using-lists-as-queues)
 * [Python stack library](https://docs.python.org/2/tutorial/datastructures.html#using-lists-as-stacks)
-