package matrix;

// Given a mxn matrix, if an element is 0, set its entire row and column to 0. Do it in place.

//STEPS

// check if first row and column are zero or not

// mark zeros on first row and colum

// use mark to set elements

// set first column and row by using marks in step 1

public class SetMatrixZeroes {

public void setZeroes(int[][] matrix) {

boolean firstRowZero = false;

boolean firstColumnZero = false;

//set first row and column zero or not

for(int i=0; i<matrix.length; i++){

if(matrix[i][0] == 0){

firstColumnZero = true;

break; } }

for(int i=0; i<matrix[0].length; i++){

if(matrix[0][i] == 0){

firstRowZero = true;

break; } }

//mark zeros on first row and column

for(int i=1; i<matrix.length; i++){

for(int j=1; j<matrix[0].length; j++){

if(matrix[i][j] == 0){

matrix[i][0] = 0;

matrix[0][j] = 0;

} } }

//use mark to set elements

for(int i=1; i<matrix.length; i++){

for(int j=1; j<matrix[0].length; j++){

if(matrix[i][0] == 0 || matrix[0][j] == 0){

matrix[i][j] = 0;

} } }

//set first column and row

if(firstColumnZero){

for(int i=0; i<matrix.length; i++)

matrix[i][0] = 0;

}

if(firstRowZero){

for(int i=0; i<matrix[0].length; i++)

matrix[0][i] = 0;

}

}

}