Question

Program to sort boundary elements in descending order in a matrix

				
					Matrix  = [9, 8, 7]
          [6, 5, 4]
          [3, 2, 1]
          
SORTED MATRIX
9  8  7
5  6  4
3  2  1

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Code

Java

Python

Java

				
					import java.util.Scanner;
public class SortNonBoundaryElementsOfMatrix
{
    public static void main(String[] args)
    {
        int row=0,col=0,i=0,j=0,k=0,temp=0,count=0;
        int arr[][],b[];

        Scanner sc=new Scanner(System.in);
        System.out.println("ENTER THE NUMBER OF ROW OF MATRIX");
        row=sc.nextInt();
        System.out.println("ENTER THE NUMBER OF COLUMN OF MATRIX");
        col=sc.nextInt();

        arr=new int[row][col];
        System.out.println("ENTER THE ELEMENTS IN MATRIX");
        for(i=0;i< row;i++)
        {
            for(j=0;j< col;j++)
            {
                arr[i][j]=sc.nextInt();
            }
        }
        for(i=1;i< row-1;i++)
        {
            for(j=1;j< col-1;j++)
            {
                /*counting the number of non-boundary elements*/
                count++;
            }
        }
        b=new int[count];
        System.out.println("ORIGINAL MATRIX:");
        for(i=0;i< row;i++)
        {
            for(j=0;j< col;j++)
            {
                System.out.print(arr[i][j]+" ");

            }
            System.out.println();
        }
        k=0;
        for(i=1;i< row-1;i++)
        {
            for(j=1;j< col-1;j++)
            {
                b[k]=arr[i][j];
                k++;
            }
        }

        /*sorting one-dimensional array*/
        for(i=0;i< b.length;i++)
        {
            for(j=0;j< b.length;j++)
            {
                if(b[i] > b[j])
                {
                    temp=b[i];
                    b[i]=b[j];
                    b[j]=temp;
                }
            }
        }

        k=0;
        for(i=1;i< row-1;i++)
        {
            for(j=1;j< col-1;j++)
            {
                arr[i][j]=b[k];
                k++;
            }
        }

        System.out.println("SORTED MATRIX:");
        for(i=0;i< row;i++)
        {
            for(j=0;j< col;j++)
            {
                System.out.print(arr[i][j]+" ");

            }
            System.out.println();
        }

    }
}

Python

				
					import numpy as np
row=int(input("Enter number of rows:"))
columns=int(input("Enter number of columns:"))
matrix=np.empty([row,columns],dtype=np.int)
# Taking input from user
print("Enter elements in matrix:")
for i in range(0,row):
    for j in range(0,columns):
        print("(",(i+1),",",(j+1),")",":",end="")
        matrix[i,j]=int(input())
#printing the matrix
print("Original Matrix:")
for i in range(0, row):
    print(matrix[i])
#Finding non-boundary elements and putting them in a list
nonBoundaryElements=[]
for i in range(1,row-1):
    for j in range(1,columns-1):
            nonBoundaryElements.append(matrix[i,j])

for i in range(0,len(nonBoundaryElements)):
    for j in range(0, len(nonBoundaryElements)):
        if(nonBoundaryElements[i]> nonBoundaryElements[j]):
            temp=nonBoundaryElements[i]
            nonBoundaryElements[i]=nonBoundaryElements[j]
            nonBoundaryElements[j]=temp
"""
You can also replace code from line 21 to line 26 with 
nonBoundaryElements.sort(reverse=True)
it will do the same thing.
"""
k=0
for i in range(1,row-1):
    for j in range(1,columns-1):
            matrix[i,j]=nonBoundaryElements[k]
            k=k+1
print("Matrix with sorted non-boundary elements:")
for i in range(0, row):
    print(matrix[i])