How to Create a Mirror Image of A 2D Array in Java

by Online Tutorials Library July 22, 2022

How to Create a Mirror Image of A 2D Array in Java?

It is a very interesting problem frequently asked in interviews of top IT companies like Google, Amazon, TCS, Accenture, IBM etc. By solving the problem, one wants to check the logical ability, critical thinking, and problem-solving skill of the interviewee. So, in this section, we are going to discuss how to create a mirror image of a 2D array in Java with different approaches and logic. Also, we will create Java programs for the same.

Problem Statement

We have given an array of m x n (where m is the number of rows and n is the number of columns). Print the new matrix in such a way that the new matrix is the mirror image of the original matrix.

Mirror Image

In a mirror image of a 2D array of m*n, elements of the first and the last columns are interchanged. The middle column remains fixed, as shown in the following figure. Note that only columns of a mirror image are interchanged row remains unaffected.

If the matrix is of 4*4, the second and fourth columns will also be interchanged.

Note: If in the given matrix the number of columns is odd the middle column will be fixed and the rest of the columns will be interchanged.

How to Create a Mirror Image of A 2D Array in Java

Solution to the Problem

MirrorImage.java

  import java.util.Scanner;  public class MirrorImage  {  public static void main(String args[])   {  //creating an instance of the scanner class   Scanner in = new Scanner(System.in);  System.out.print(“Enter number of rows (m): “);  //reads number of rows  int m = in.nextInt();  System.out.print(“Enter number of columns (n): “);  //reads number of columns  int n = in.nextInt();  //creating an array of m*n type  int arr[][] = new int[m][n];  //another array to store mirror image   int newArr[][] = new int[m][n];  System.out.println(“Enter array elements”);  //read array elements for row nth row  for (int i = 0; i < m; i++)   {  System.out.println(“Enter Row “+ (i+1) + “:”);  for (int j = 0; j < n; j++)   {  arr[i][j] = in.nextInt();  }  }  //prints the input array   System.out.println(“Input Array:”);  for (int i = 0; i < m; i++)   {  for (int j = 0; j < n; j++)   {  System.out.print(arr[i][j] + “t”);  }  System.out.println();  }  //interchanging (swapping) matrix elements  for (int j = 0; j < n; j++)   {  for (int i = 0; i < m; i++)   {  newArr[i][n – 1 – j] = arr[i][j];   }  }  //prints mirror image of the given matrix  System.out.println(“Mirror Image of Array:”);  for (int i = 0; i < m; i++)   {  for (int j = 0; j < n; j++)   {  System.out.print(newArr[i][j] + “t”);  }  System.out.println();  }  }  }  

Output:

How to Create a Mirror Image of A 2D Array in Java

Next TopicAdd Numbers Represented by Linked Lists in Java

How to Create a Mirror Image of A 2D Array in Java

How to Create a Mirror Image of A 2D Array in Java?

Problem Statement

Mirror Image

Note: If in the given matrix the number of columns is odd the middle column will be fixed and the rest of the columns will be interchanged.

Solution to the Problem

Zoom Alternatives

Accounting Books

You may also like