nekedome / project-euler

solutions/problem22.py

"""
Project Euler Problem 22: Names Scores
======================================

.. module:: solutions.problem22
   :synopsis: My solution to problem #22.

The source code for this problem can be
`found here <https://bitbucket.org/nekedome/project-euler/src/master/solutions/problem22.py>`_.

Problem Statement
#################

Using `names.txt <https://projecteuler.net/project/resources/p022_names.txt>`_
(right click and 'Save Link/Target As...'), a :math:`46` KB text file containing over five-thousand first names, begin

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by sorting it into alphabetical order. Then working out the alphabetical value for each name, multiply this value by its

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alphabetical position in the list to obtain a name score.

For example, when the list is sorted into alphabetical order, ``COLIN``, which is worth
:math:`3 + 15 + 12 + 9 + 14 = 53`, is the :math:`938^{th}` name in the list. So, ``COLIN`` would obtain a score of

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:math:`938 \\times 53 = 49714`.

What is the total of all the name scores in the file?

Solution Discussion
###################

Nothing clever is needed or used here. Simply load the name, sort them, and compute the required score.

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Solution Implementation
#######################

.. literalinclude:: ../../solutions/problem22.py
   :language: python
   :lines: 38-
"""

from lib.util import load_dataset


def score(name: str) -> int:
    """ Compute the numeric score of `name` by summing the individual letter scores

    The letter scores are defined as:

    .. math::

        A & \\rightarrow 1 \\\\
        B & \\rightarrow 2 \\\\
          & \\dots \\\\
        Z & \\rightarrow 26

    :param name: the name to score
    :return: the score of `name`

    >>> score("COLIN")
    53  # 3 + 15 + 12 + 9 + 14
    """

    scores = {chr(i): i - ord('A') + 1 for i in range(ord('A'), ord('Z') + 1)}
    return sum([scores[character] for character in name])


def solve():
    """ Compute the answer to Project Euler's problem #22 """
    names = load_dataset("problems", "p022_names", separator=",")
    names = [name.strip("\"") for name in names]  # strip quotes off each name
    names.sort()  # ascending lexicographical order
    answer = 0
    for pos, name in enumerate(names):
        answer += (pos + 1) * score(name)  # one-base the positions within the sorted list
    return answer


expected_answer = 871198282

The name expected_answer does not conform to the constant naming conventions ((([A-Z_][A-Z0-9_]*)|(__.*__))$).