Array/Homework

• Homework

Homework

Write a program that randomly fills in 0s and 1s into an n-by-n matrix, prints the matrix, and finds the rows and columns with the most 1s. (Hint: Use two ArrayLists to store the row and column indices with the most 1s.)

Here is a sample run of the program, printed in the console:

Enter the array size n: 4
The random array is
0011
0011
1101
1010
The largest row index: 2
The largest column index: 2, 3 

import java.util.ArrayList;
import java.util.Scanner;

public class MatrixMaxOnes {
    public static void main(String[] args) {
        Scanner input = new Scanner(System.in);

        System.out.print("Enter the array size n: ");
        int n = input.nextInt();

        int[][] matrix = new int[n][n];
        for (int i = 0; i < n; i++) {
            for (int j = 0; j < n; j++) {
                matrix[i][j] = (int) (Math.random() * 2);
            }
        }

        System.out.println("The random array is");
        for (int i = 0; i < n; i++) {
            for (int j = 0; j < n; j++) {
                System.out.print(matrix[i][j]);
            }
            System.out.println();
        }

        int maxRowCount = 0;
        ArrayList<Integer> maxRows = new ArrayList<>();
        for (int i = 0; i < n; i++) {
            int rowCount = 0;
            for (int j = 0; j < n; j++) {
                rowCount += matrix[i][j];
            }
            if (rowCount > maxRowCount) {
                maxRowCount = rowCount;
                maxRows.clear();
                maxRows.add(i);
            } else if (rowCount == maxRowCount) {
                maxRows.add(i);
            }
        }

        int maxColCount = 0;
        ArrayList<Integer> maxCols = new ArrayList<>();
        for (int j = 0; j < n; j++) {
            int colCount = 0;
            for (int i = 0; i < n; i++) {
                colCount += matrix[i][j];
            }
            if (colCount > maxColCount) {
                maxColCount = colCount;
                maxCols.clear();
                maxCols.add(j);
            } else if (colCount == maxColCount) {
                maxCols.add(j);
            }
        }

        System.out.println("The largest row index: " + listToString(maxRows));
        System.out.println("The largest column index: " + listToString(maxCols));
    }

    private static String listToString(ArrayList<Integer> list) {
        StringBuilder sb = new StringBuilder();
        for (int i = 0; i < list.size(); i++) {
            sb.append(list.get(i));
            if (i < list.size() - 1) {
                sb.append(", ");
            }
        }
        return sb.toString();
    }
}

MatrixMaxOnes.main(null);

Enter the array size n: The random array is
0011000
0000010
0110011
1111001
1101001
0001000
0001001
The largest row index: 3
The largest column index: 3