Leetcode：73.Set Matrix Zeroes

public void setZeroes(int[][] matrix) {
int col0 = 1, rows = matrix.length, cols = matrix[0].length;

for (int i = 0; i < rows; i++) {
if (matrix[i][0] == 0) col0 = 0;//这一行的第一个等于0
for (int j = 1; j < cols; j++)
if (matrix[i][j] == 0)      //i行j列等于0
matrix[i][0] = matrix[0][j] = 0; //i行第一个或者j列第一个设置为0
}

//反向遍历
for (int i = rows - 1; i >= 0; i--) {
for (int j = cols - 1; j >= 1; j--)
if (matrix[i][0] == 0 || matrix[0][j] == 0)
matrix[i][j] = 0;
if (col0 == 0) matrix[i][0] = 0;
}
}