Reverse Array Java | HackerRank

 

Title: Reversing an Array: A HackerRank DSA Challenge Explained

Introduction: In the world of competitive programming, HackerRank is a renowned platform where developers sharpen their coding skills by solving algorithmic challenges across various domains. One such challenge involves reversing an array, a fundamental problem in Data Structures and Algorithms (DSA). In this blog post, we'll delve into the intricacies of this challenge, explore the underlying concepts, and provide a detailed solution.

Understanding the Challenge: The task is simple: given an array of integers, reverse its elements in-place. This means altering the array itself without utilizing additional data structures. While the problem may seem straightforward, its solution requires a sound understanding of array manipulation techniques.

Solution Approach: Let's break down the solution approach into steps:

1. Input: The first step involves receiving input from the user. In HackerRank, inputs are typically provided through stdin (standard input).

2. Array Reversal Logic: After obtaining the array elements, we need to reverse them. The reversal process usually involves swapping elements from both ends of the array towards the middle until they meet. This can be efficiently achieved using a two-pointer technique.

3. Output: Finally, we print the reversed array to stdout (standard output).

Code Implementation: Here's the Java code implementation for the problem:

import java.util.Scanner;

public class Main {

    public static void main(String[] args) {

        Scanner scanner = new Scanner(System.in);

        int num = scanner.nextInt();

        int[] arr = new int[num];

        for (int i = 0; i < num; i++) {

            arr[i] = scanner.nextInt();

        }

       

        for(int i = num-1 ; i>=0 ;i--){

             System.out.print(arr[i] + " ");

        }

    }

}