Project Euler Problem 22: Names Scores

The source code for this problem can be found here.

Problem Statement

Using names.txt (right click and ‘Save Link/Target As…’), a \(46\) KB text file containing over five-thousand first names, begin by sorting it into alphabetical order. Then working out the alphabetical value for each name, multiply this value by its alphabetical position in the list to obtain a name score.

For example, when the list is sorted into alphabetical order, COLIN, which is worth \(3 + 15 + 12 + 9 + 14 = 53\), is the \(938^{th}\) name in the list. So, COLIN would obtain a score of \(938 \times 53 = 49714\).

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.

Solution Implementation

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
solutions.problem22.score(name)

Compute the numeric score of name by summing the individual letter scores

The letter scores are defined as:

\[\begin{split}A & \rightarrow 1 \\ B & \rightarrow 2 \\ & \dots \\ Z & \rightarrow 26\end{split}\]
Parameters:name (str) – the name to score
Return type:int
Returns:the score of name 
>>> score("COLIN")
53  # 3 + 15 + 12 + 9 + 14
solutions.problem22.solve()

Compute the answer to Project Euler’s problem #22