public static void main(String[] strs) {

int[][] matrix = {

{0,0,0,5},{4,3,1,4},{0,1,1,4},{1,2,1,3},{0,0,1,1}

};

setZeroes(matrix);

}

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

if (matrix == null || matrix.length == 0

|| matrix[0].length == 0) {

return;

}

boolean row1Zero = false;

boolean col1Zero = false;

int rows = matrix.length;

int cols = matrix[0].length;

// Determine if the first column should be Zero.

for (int i = 0; i < rows; i++) {

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

col1Zero = true;

break;

}

}

// Determine if the first row should be Zero.

for (int i = 0; i < cols; i++) {

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

row1Zero = true;

break;

}

}

// we use the first row and the first col as the flag to record the

// cells whether or not set to 0.

for (int i = 1; i < rows; i++) {

for (int j = 1; j < cols; j++) {

// 注意了，这个矩阵是0和非0，并不是0和1.

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

// set the flag in the first line and the first column

matrix[i][0] = 0;

matrix[0][j] = 0;

}

}

}

// set the inner cells.

// Be careful: i, j start from 1.

for (int i = 1; i < rows; i++) {

for (int j = 1; j < cols; j++) {

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

|| matrix[0][j] == 0) {

matrix[i][j] = 0;

}

}

}

// set the first row.

if (row1Zero) {

for (int i = 0; i < cols; i++) {

matrix[0][i] = 0;

}

}

// set the first col.

if (col1Zero) {

for (int i = 0; i < rows; i++) {

matrix[i][0] = 0;

}

}

return;

}