40 Algorithms Every Programmer Should Know

The basic idea behind the use of stacks and queues

Let's look into the basic idea behind the use of stacks and queues using an analogy. Let's assume that we have a table where we put our incoming mail from our postal service, for example, Canada Mail. We stack it until we get some time to open and look at the mail, one by one. There are two possible ways of doing this:

• We put the letter in a stack and whenever we get a new letter, we put it on the top of the stack. When we want to read a letter, we start with the one that is on top. This is what we call a stack. Note that the latest letter to arrive will be on the top and will be processed first. Picking up a letter from the top of the list is called a pop operation. Whenever a new letter ...