leetcode 43: Set Matrix Zeroes

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

uncompleted

class Solution {
public:
void setZeroes(vector<vector<int> > &matrix) {
// Start typing your C/C++ solution below
// DO NOT write int main() function

if( matrix.size() == 0 ) return;

size_t row = matrix.size();
size_t col = matrix[0].size();

bool row_flag = false, col_flag = false;

for( int i=0; i<row; i++) {
if( matrix[i][0] == 0 ) {
row_flag = true;
}
}

for( int j=0; j<col; j++) {
if( matrix[0][j] == 0 ) {
col_flag = true;
}
}

for( int i=1; i< row; i++) {
for ( int j=1; j< col; j++) {
if( matrix[i][j] == 0 ) {
matrix[0][j] = 0;
matrix[i][0] = 0;
}
}
}

for( int i=0; i<matrix.size(); i++) {
if(matrix[i][0] == 0) {
for( int j=1; j<matrix[0].size(); j++){
matrix[i][j] = 0;
}
} else if(row_flag) {
matrix[i][0] = 0;
}
}

for( int j=0; j<matrix[0].size(); j++) {
if(matrix[0][j] == 0) {
for( int i=1; i<matrix.size(); i++){
matrix[i][j] = 0;
}
} else if(col_flag) {
matrix[0][j] = 0;
}
}
}
};

java version passed.

public class Solution {
public void setZeroes(int[][] matrix) {
// Start typing your Java solution below
// DO NOT write main() function
if(matrix==null || matrix[0]==null ) return;
//if(matrix.length==1) return; [[0,1]] matrix is not square not rectangle. when u modify at one place may influence many.
int m = matrix.length;
int n  = matrix[0].length;

boolean firstRow = false;
boolean firstCol = false;

for(int j=0; j<n; j++) {
if(matrix[0][j]==0) {
firstRow = true;
break;
}
}

for(int i=0; i<m; i++) {
if(matrix[i][0]==0) {
firstCol = true;
break;
}
}

for(int i=1; i<m; i++) {
for(int j=1; j<n; j++) {
if(matrix[i][j] == 0) {
matrix[0][j] = 0;
matrix[i][0] = 0;
}
}
}

for(int i=1; i<m; i++) {
for(int j=1; j<n; j++) {
if(matrix[0][j]==0 || matrix[i][0]==0) {
matrix[i][j]=0;
}
}
}

if(firstRow) {
for(int j=0; j<n;j++) {
matrix[0][j] = 0;
}
}

if(firstCol) {
for(int i=0; i<m; i++) {
matrix[i][0] = 0;
}
}
}
}