Putting It All Together

Congratulations! You've learned about stacks in-depth, including their properties, implementation, common operations, applications, and complexity analysis. Let's summarize the key concepts you've learned:

• Stack Definition: A stack is a linear data structure that follows the Last-In-First-Out (LIFO) principle. Elements are added or removed from the top of the stack.

• Stack Implementation: Stacks can be implemented using arrays or linked lists. Array-based implementation provides constant time access to the top element, while linked list-based implementation allows for dynamic sizing.

• Stack Operations: The fundamental operations on a stack are push (adding an element to the top), pop (removing the top element), and peek (retrieving the top element without modifying the stack).

• Applications of Stacks: Stacks find applications in various real-world scenarios, such as web browsers' navigation history, undo/redo functionality in applications, syntax parsing, depth-first search (DFS) algorithm, and more.

• Stack Complexity Analysis: Stack operations, including push, pop, and peek, have a time complexity of O(1) as they take constant time. The space complexity of a stack is O(n) as it depends on the number of elements stored.

Let's see a practical example of using a stack in Java:

1<<code>>

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class Main {

  public static void main(String[] args) {

    // replace with your Java logic here

    Stack<String> stack = new Stack<String>();

​

    stack.push("Hello");

    stack.push("World");

​

    System.out.println(stack.peek());

    System.out.println(stack.pop());

    System.out.println(stack.peek());

  }

}