Java Program to Sort 2D Array Across Columns

// Java Program to Sort 2D array across Columns

// Importing required classes
import java.io.*;
import java.lang.*;
import java.util.*;

// Main class
class GFG {

    // Main driver method
    public static void main(String[] args)
        throws java.lang.Exception
    {

        // Custom input for 2D array
        int[][] arr = { { 7, 2, 0, 5, 1 },
                        { 3, 8, 2, 9, 14 },
                        { 5, 1, 0, 5, 2 },
                        { 4, 2, 6, 0, 1 } };

        // Display message for better readability
        System.out.println("Matrix without sorting \n");

        // Nested iteration to display matrix
        for (int i = 0; i < 4; i++) {

            for (int j = 0; j < 5; j++) {

                // Printing elements of 2D matrix
                System.out.print(arr[i][j] + " ");
            }
            // New line as we are done with row
            System.out.println();
        }

        // Creating an object of Vector class
        Vector<Integer> v = new Vector<>();

        // Nested iteration using for loops
        for (int i = 0; i < 5; i++) {
            for (int j = 0; j < 4; j++) {

                // Adding elements of columns in vector
                // using add() method
                v.add(arr[j][i]);
            }

            // Sorting elements in vector
            // using sort() method
            Collections.sort(v);

            for (int j = 0; j < 4; j++) {

                // Sorted elements are pushed back
                // from vector to column
                arr[j][i] = v.get(j);
            }

            // Elements are removed from vector for
            // fresh sorting using remove() method
            v.removeAll(v);
        }

        // Printing matrix after sorting
        System.out.println("Matrix after sorting \n");

        for (int i = 0; i < 4; i++) {
            for (int j = 0; j < 5; j++) {

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

            System.out.println();
        }
    }
}