Number of Path in A Matrix 2

    static Integer number_of_paths(ArrayList<ArrayList<Integer>> matrix) {
        int nr = matrix.size();
        int nc = matrix.get(0).size();
        int modulo = 1000000007;

        //edge case
        if (matrix.get(0).get(0) == 0 || matrix.get(nr-1).get(nc-1) == 0) {
            return 0;
        }

        int[][] now = new int[nr][nc];

        //if we can reach cell (0,0) then number of ways to reach it is 1
        now[0][0] = 1;

        //Filling the cells in the first row.
        for (int c = 1; c < nc; c++){
            if (matrix.get(0).get(c) == 1 && now[0][c-1] == 1) {
                now[0][c] = 1;
            }
        }

        //Filling the cells in the frist column
        for (int r = 1; r < nr; r++) {
            if (matrix.get(r).get(0) == 1 && now[r-1][0] == 1) {
                now[r][0] = 1;
            }
        }

        /*number of ways to reach
        cell(i,j) = number of ways to reach cell(i-1,j) + number of ways to reach cell (i,j-1)*/
        for (int r = 1; r < nr; r++) {
            for (int c = 1; c < nc; c++) {
                now[r][c] = (now[r-1][c] % modulo + now[r][c-1] % modulo) % modulo;
            }
        }

        return now[nr-1][nc-1] % modulo;
    }