about_scoring_project.py

#!/usr/bin/env python
# -*- coding: utf-8 -*-
from runner.koan import Koan

# Greed is a dice game where you roll up to five dice to accumulate
# points.  The following "score" function will be used calculate the
# score of a single roll of the dice.
#
# A greed roll is scored as follows:
#
# * A set of three ones is 1000 points
#
# * A set of three numbers (other than ones) is worth 100 times the
#   number. (e.g. three fives is 500 points).
#
# * A one (that is not part of a set of three) is worth 100 points.
#
# * A five (that is not part of a set of three) is worth 50 points.
#
# * Everything else is worth 0 points.
#
#
# Examples:
#
# score([1,1,1,5,1]) => 1150 points
# score([2,3,4,6,2]) => 0 points
# score([3,4,5,3,3]) => 350 points
# score([1,5,1,2,4]) => 250 points
import math
import functools
import collections

SET = 3


def score(dice_rolls):
    if not dice_rolls:
        return 0

    rolls_to_counts = collections.Counter(dice_rolls)
    rolls_to_scoring_counts = _get_rolls_to_scoring_counts(rolls_to_counts)

    total_points = 0
    total_points += _calc_set_points(rolls_to_scoring_counts)
    total_points += _calc_nonset_points(rolls_to_scoring_counts)
    return total_points


def _get_rolls_to_scoring_counts(rolls_to_counts):
    '''Return a dict of rolls to scoring counts.

    ScoringCounts is a namedtuple: ScoringCounts(sets, nonsets)
    containing the set count and nonset count as values for each roll key.

    '''

    rolls_to_scoring_counts = {}
    ScoringCounts = collections.namedtuple('ScoringCounts', 'sets nonsets')

    for roll in rolls_to_counts:
        cur_roll_count = rolls_to_counts[roll]

        if _roll_has_a_set(cur_roll_count):
            set_count = math.floor(cur_roll_count / SET)
            nonset_count = cur_roll_count % SET
        else:
            set_count = 0
            nonset_count = cur_roll_count

        rolls_to_scoring_counts[roll] = ScoringCounts(set_count, nonset_count)
    return rolls_to_scoring_counts


def _roll_has_a_set(roll_count):
    return roll_count >= SET


def _calc_set_points(rolls_to_scoring_counts):
    def _accumulate_set_points(accum, roll):
        SET_ROLL_TO_POINTS = {
            1: 1000,
            2: 2 * 100,
            3: 3 * 100,
            4: 4 * 100,
            5: 5 * 100,
            6: 6 * 100
        }
        return accum + SET_ROLL_TO_POINTS[roll] * rolls_to_scoring_counts[roll].sets

    return functools.reduce(_accumulate_set_points, rolls_to_scoring_counts, 0)


def _calc_nonset_points(rolls_to_scoring_counts):
    def _accumlate_nonset_points(accum, roll):
        ROLL_TO_POINTS = {
            1: 100,
            2: 0,
            3: 0,
            4: 0,
            5: 50,
            6: 0
        }
        return accum + ROLL_TO_POINTS[roll] * rolls_to_scoring_counts[roll].nonsets

    return functools.reduce(_accumlate_nonset_points, rolls_to_scoring_counts, 0)


# If interested in getting tests to run, check the project https://github.com/gregmalcolm/python_koans/tree/master/python3

# For ref:
# class Koan(unittest.TestCase):
#     pass

class AboutScoringProject(Koan):
    def test_score_of_an_empty_list_is_zero(self):
        self.assertEqual(0, score([]))

    def test_score_of_a_single_roll_of_5_is_50(self):
        self.assertEqual(50, score([5]))

    def test_score_of_a_single_roll_of_1_is_100(self):
        self.assertEqual(100, score([1]))

    def test_score_of_multiple_1s_and_5s_is_the_sum_of_individual_scores(self):
        self.assertEqual(300, score([1, 5, 5, 1]))

    def test_score_of_single_2s_3s_4s_and_6s_are_zero(self):
        self.assertEqual(0, score([2, 3, 4, 6]))

    def test_score_of_a_triple_1_is_1000(self):
        self.assertEqual(1000, score([1, 1, 1]))

    def test_score_of_other_triples_is_100x(self):
        self.assertEqual(200, score([2, 2, 2]))
        self.assertEqual(300, score([3, 3, 3]))
        self.assertEqual(400, score([4, 4, 4]))
        self.assertEqual(500, score([5, 5, 5]))
        self.assertEqual(600, score([6, 6, 6]))

    def test_score_of_mixed_is_sum(self):
        self.assertEqual(250, score([2, 5, 2, 2, 3]))
        self.assertEqual(550, score([5, 5, 5, 5]))
        self.assertEqual(1150, score([1, 1, 1, 5, 1]))

    def test_ones_not_left_out(self):
        self.assertEqual(300, score([1, 2, 2, 2]))
        self.assertEqual(350, score([1, 5, 2, 2, 2]))

    def test_score_of_rolls_larger_than_5(self):
        self.assertEqual(0, score([2, 2, 3, 4, 6, 6]))

    def test_score_of_larger_than_5_with_set(self):
        self.assertEqual(600, score([2, 2, 3, 4, 6, 6, 6]))
        self.assertEqual(600, score([2, 2, 3, 6, 6, 6, 6]))

    def test_score_of_larger_than_5_with_multiple_set(self):
        self.assertEqual(600*2, score([2, 2, 3, 4, 6, 6, 6, 6, 6, 6]))
        self.assertEqual(1000 + 600*2, score([1, 1, 1, 4, 6, 6, 6, 6, 6, 6]))
        self.assertEqual(1000 + 100 + 600*2, score([1, 1, 1, 1, 6, 6, 6, 6, 6, 6]))