Python - Tuples(reducible words)

Think Python

開発環境

• OS X El Capitan - Apple (OS)
• Emacs (Text Editor)
• Python 3.5 (プログラミング言語)

Think Python (Allen B. Downey (著)、 O'Reilly Media)のChapter 12.(Tuples)のExercises 12-4.(No. 2897)を取り組んでみる。

Exercises 12-4.(No. 2897)

コード(Emacs)

#!/usr/bin/env python3
# -*- coding: utf-8 -*-


def get_words(filename):
    with open(filename) as f:
        words = {line.strip() for line in f}
    return words | {'i', 'a', ''}


def children(word):
    return {word[:i] + word[i + 1:] for i, _ in enumerate(word)}

reducible_words = {'i', 'a', ''}


def is_reducible(word, words):
    if word in reducible_words:
        return True
    if word == '':
        return True
    for child in children(word):
        if (child in words) and is_reducible(child, words):
            reducible_words.add(word)
            return True
    return False


if __name__ == '__main__':
    filename = 'words.txt'
    words = get_words(filename)
    reducibles = filter(lambda word: is_reducible(word, words), words)
    print(sorted(reducibles, key=len, reverse=True)[0])

入出力結果(Terminal, IPython)

$ ./sample4.py
complecting
$