def calculate_single_gpa(score):
    """
    Calculate gpa with a score.

    Use a lookup table to calculate a single gpa.
    Empty scores or scores not between 0 and 100 will be regarded as 0.
    """
    lookup_table = [0.0] * 60 + [1.0] * 4 + [1.5] * 4 + [2.0] * 4 + \
        [2.3] * 3 + [2.7] * 3 + [3.0] * 4 + [3.3] * 3 + [3.7] * 5 + [4.0] * 11
    return 0.0 if score is None or score < 0 or score > 100 else lookup_table[
        int(score)]