Stacks and Queues

As a senior engineer with extensive experience in data structures and algorithms, you have undoubtedly encountered the concepts of stacks and queues. These two data structures play a crucial role in solving a wide range of programming problems.

Stack is a linear data structure that follows the Last-In-First-Out (LIFO) principle. Elements are added and removed from the top of the stack. Think of it as a stack of books - the last book you put on the stack is the first one you can remove.

1Stack<Integer> stack = new Stack<>();
2stack.push(1);
3stack.push(2);
4stack.push(3);
5int topElement = stack.peek();
6stack.pop(); // Removes the top element

In the code above, we are creating a stack using the Stack class in Java. We add elements to the stack using the push method, retrieve the top element using the peek method, and remove the top element using the pop method.

A queue, on the other hand, follows the First-In-First-Out (FIFO) principle. Elements are added at the rear and removed from the front. Imagine a queue of people waiting in line - the person who has been waiting the longest gets served first.

1Queue<Integer> queue = new LinkedList<>();
2queue.add(1);
3queue.add(2);
4queue.add(3);
5int frontElement = queue.peek();
6queue.remove(); // Removes the front element

In the code above, we are creating a queue using the LinkedList class in Java. We add elements to the queue using the add method, retrieve the front element using the peek method, and remove the front element using the remove method.

Stacks and queues have various real-life applications. For example, a stack can be used to implement the undo feature in a text editor, while a queue can be used to process tasks in a multi-threaded environment.

By understanding the principles and operations of stacks and queues, you can choose the appropriate data structure for your specific problem and efficiently solve it.

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class Main {

  public static void main(String[] args) {

    // Code for explanation

  }

}