[Solved] A Boolean Matrix Problem Contest Problem

A Boolean Matrix Problem: You are given a matrix Mat of m rows and n columns. The matrix is boolean so the elements of the matrix can only be either 0 or 1.
Now, if any row of the matrix contains a 1, then you need to fill that whole row with 1. After doing the mentioned operation, you need to print the modified matrix.

A Boolean Matrix Problem Contest

Input:
The first line of input contains T denoting the number of testcases. T testcases follow.
The first line of each testcase contains m and n denoting number of rows and number of columns.
Then next m lines contain n elements denoting the elements of the matrix.

Output:
For each testcase, in a new line, print the modified matrix.

Constraints:
1 <= T <= 100
1 <= m, n <= 900
Mat_ij ∈ {0,1}

Examples:
Input:
2
5 4
1 0 0 0
0 0 0 0
0 1 0 0
0 0 0 0
0 0 0 1
1 2
0 0
Output:
1 1 1 1
0 0 0 0
1 1 1 1
0 0 0 0
1 1 1 1
0 0

Explanation:
Testcase1: rows = 5 and columns = 4
The given matrix is
1 0 0 0
0 0 0 0
0 1 0 0
0 0 0 0
0 0 0 1
Evidently, the first row contains a 1 so fill the whole row with 1. The third row also contains a 1 so that row will be filled too. Finally, the last row contains a 1 and therefore it needs to be filled with 1 too.
The final matrix is
1 1 1 1
0 0 0 0
1 1 1 1
0 0 0 0
1 1 1 1

Solution:

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.StringTokenizer;

public class BooleanMatrixProblem {
    static class FastReader{
        BufferedReader br;
        StringTokenizer st;
        public FastReader(){
            br = new BufferedReader(new InputStreamReader(System.in));
        }
        String next(){
            while (st == null || !st.hasMoreElements()){
                try {
                    st = new StringTokenizer(br.readLine());
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            return st.nextToken();
        }
        String nextLine(){
            String str = "";
            try {
                str = br.readLine();
            }catch (IOException e){
                e.printStackTrace();
            }
            return str;
        }
        int nextInt(){
            return Integer.parseInt(next());
        }
    }
    public static void main(String[] args) {
        FastReader fr = new FastReader();
        int t = fr.nextInt();
        while (t-->0){
            int m = fr.nextInt();
            int n = fr.nextInt();

            String string1 = "";
            for(int i=0;i<n;i++)
                string1 = string1 + "1 ";

            String string2 = "";
            for(int i=0;i<n;i++)
                string2 = string2 + "0 ";

            int[][] matrixx = new int[m][n];

            int count = 0;

            ArrayList<Integer> list = new ArrayList<Integer>();

            for(int i=0;i<m;i++)
            {
                count = 0;

                for(int j=0;j<n;j++)
                {
                    matrixx[i][j] = fr.nextInt();

                    if(matrixx[i][j]==1 && count==0)
                    {
                        list.add(j);
                        count++;
                    }
                }

                if(count!=0)
                    System.out.println(string1);
                else
                    System.out.println(string2);
            }

        }
    }
}

Happy Learning – If you require any further information, feel free to contact me.