Leetcode 73. Set Matrix Zeroes

Given a m x n matrix,
if an element is 0, set its entire row and column to 0. Do it in place.public class Solution {
public void setZeroes(int[][] matrix) {
int m = matrix.length;
if(m == 0)
return;
int n = matrix[0].length;
boolean firstRow = false;
boolean firstColumn = false;
for(int i = 0; i < m; i++){
if(matrix[i][0] == 0)
firstColumn = true;
}
for(int i = 0; i < n; i++){
if(matrix[0][i] == 0)
firstRow = true;
}
for(int i = 1; i < m; i++){
for(int j = 1; j < n; j++){
if(matrix[i][j] == 0){
matrix[i][0] = 0;
matrix[0][j] = 0;
}
}
}
for(int i = 0; i < m; i++){
if(matrix[i][0] == 0){
for(int j = 0; j < n; j++){
matrix[i][j] = 0;
}
}
}
for(int i = 0; i < n; i++){
if(matrix[0][i] == 0){
for(int j = 0; j < m;j++){
matrix[j][i] = 0;
}
}
}
if(firstRow){
for(int i = 0; i < n; i++){
matrix[0][i] = 0;
}
}
if(firstColumn){
for(int i = 0; i < m; i++){
matrix[i][0] = 0;
}
}
}
}