Making entire row and column of matrix to zero if one element is zero | alternative approach

Given a matrix if an element in the matrix is 0 then you will have to set its entire column and row to 0 and then return the matrix.

 

/**

 * Given a matrix if an element in the matrix is 0 then you will have to set its entire column and row to 0 and then return the matrix.

 */

package com.striver.sde.practice;

import java.util.ArrayList;

import java.util.List;

/**

 * @author apple

 *

 */

public class MatrixZero {

/**

* @param args

*/

public static void main(String[] args) {

int[][] input = { { 1, 1, 1 }, { 1, 0, 1 }, { 1, 1, 1 } };

MatrixZero m = new MatrixZero();

// m.findSolution(input);

m.findSolution2(input);

}

private void findSolution2(int[][] input) {

int len = input.length;

List rows = new ArrayList<>();

List cols = new ArrayList<>();

for (int row = 0; row < len; row++) {

for (int col = 0; col < len; col++) {

if (input[row][col] == 0) {

rows.add(row);

cols.add(col);

}

}

}

for (int row = 0; row < len; row++) {

for (int col = 0; col < len; col++) {

if(rows.contains(row)) {

input[row][col] =0;

}

if(cols.contains(col)) {

input[row][col] =0;

}

}

}

System.out.println(input);

}

private void findSolution(int[][] input) {

int[][] output = input.clone();

int len = input.length;

for (int row = 0; row < len; row++) {

for (int col = 0; col < len; col++) {

if (input[row][col] == 0) {

modifyMatrix(row, col, output, len);

}

}

}

}

private void modifyMatrix(int row, int col, int[][] output, int len) {

if (row == 0) {

int r = row;

while (r < len) {

output[r][col] = 0;

r = r + 1;

}

} else if (row == len) {

int r = row;

while (r >= 0) {

output[r][col] = 0;

r = r - 1;

}

} else {

}

}

}