1.7 Matrix Zero

Write an algorithm such that if an element in an MxN matrix is 0, its
entire rowand column are set to 0.

public static void matrixZero(int[][] matrix) {
    if (matrix.length == 0 || matrix[0].length == 0)
        return;

    int m = matrix.length;
    int n = matrix[0].length;
    boolean rowZero = false;
    boolean colZero = false;

    // save first row and first col
    for (int i = 0; i < m; i++)
        if (matrix[i][0] == 0)
            rowZero = true;
    for (int i = 0; i < n; i++)
        if (matrix[0][i] == 0)
            colZero = true;

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

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

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

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

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