73.Set_Matrix_Zeroes.java

class Solution {
    public void setZeroes(int[][] matrix) {
        int rows = matrix.length;
        int cols = matrix[0].length;
        boolean firstRow = false;
        for (int r=0; r<rows; r++) {
            for (int c=0; c<cols; c++) {
                if (matrix[r][c] == 0) {
                    if (r > 0) {
                        matrix[0][c] = 0;
                        matrix[r][0] = 0;
                    } else {
                        firstRow = true;
                    }
                }
            }
        }
        for (int r=1; r<rows; r++) {
            for (int c=1; c<cols; c++) {
                if (matrix[0][c] == 0 || matrix[r][0] == 0) {
                    matrix[r][c] = 0;
                }
            }
        }
        if (matrix[0][0] == 0) {
            for (int r=0; r<rows; r++) {
                matrix[r][0] = 0;
            }
        }
        if (firstRow) {
            for (int c=0; c<cols; c++) {
                matrix[0][c] = 0;
            }
        }
    }
}