Rotate Matrix by 90 Degrees Clockwise in Java | Clockwise Rotation Matrix | topperbhai.com

Rotate a Matrix by 90 Degree Clockwise Java

In this tutorial, we will write a Java program to rotate a matrix by 90 degrees in clockwise rotation. 

 

The clockwise rotation is also called  as the right rotation of the matrix.

 

Rotate Matrix by 90 Degree Clockwise Algorithm:-

Step 1:  Enter the number of rows (r).

Step 2:  Enter the number of columns (c).

Step 3:  Enter the elements of Matrix (arr[i][j]).

Step 4:  Swap the elements of the first column with the last column (if matrix is of 3*3 order). The second column remains the same.

Step 5:  Print the "Rotated Matrix".

 

Note: Rotation is possible if and only if matrix have the same number of rows and columns.

 

 

Now, Let's understand through an example. Suppose, the given matrix is :

 

 

Let's find the transpose of the above matrix. 

 

 

To rotate matrix, swap the first column of matrix with the last column of matrix. 

 

 

The above matrix is now a rotated matrix by 90 degrees.

If the given matrix is 4*4 matrix, swap the first column with the last column and the second column with the third column. For example, consider the following figure.

 

 

Rotate Matrix 90 Degrees Clockwise

 import java.util.*;  
 class Clockwise_Rotate  
 {  
   public static void main()  
   {  
     Scanner sc=new Scanner(System.in);  
     System.out.println("Enter the number of Rows");  
     int r=sc.nextInt();  
     System.out.println("Enter the number of Columns");  
     int c=sc.nextInt();  
     int arr[][]=new int[r][c];  
     System.out.println("Enter the elements of Matrix");  
     for(int i=0;i<r;i++)  
     {  
       for(int j=0;j<c;j++)  
       {          
         arr[i][j]=sc.nextInt();  
       }        
     }  
     System.out.println("Input Matrix Is:");  
     for(int i=0;i<r;i++)  
     {  
       for(int j=0;j<c;j++)  
       {          
         System.out.print(arr[i][j]+" ");  
       }  
       System.out.println("");       
     }  
     System.out.println("Matrix After Rotation Is:");  
     for(int j=0;j<c;j++)  
     {  
       for(int i=r-1;i>=0;i--)  
       {          
         System.out.print(arr[i][j]+"\t");  
       }  
       System.out.println(" ");       
     }  
   }  
 }  
 -------------  
 OUTPUT:-  
 -------------  
 Enter the number of Rows  
 4  
 Enter the number of Columns  
 4  
 Enter the elements of Matrix  
 1  
 5  
 6  
 4  
 2  
 3  
 5  
 7  
 8  
 9  
 3  
 1  
 6  
 4  
 5  
 2  
 Input Matrix Is:  
 1 5 6 4   
 2 3 5 7   
 8 9 3 1   
 6 4 5 2   
 Matrix After Rotation is:  
 6  8  2  1     
 4  9  3  5     
 5  3  5  6     
 2  1  7  4