89 lines
2.3 KiB
Python
89 lines
2.3 KiB
Python
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def get_words():
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with open("../txt/e098.txt", "r") as f:
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words = list(map(lambda w: w.strip().lower(), f.readlines()))
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words.sort(key=len, reverse=True)
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return words
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def get_pair_subsets(xs):
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""" Returns all subsets of size two. """
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r = [(xs[i], xs[j])
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for i in range(len(xs))
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for j in range(i + 1, len(xs))]
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return r
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def find_anagrams(xs):
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anagrams = {}
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for x in xs:
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x_tuple = tuple(sorted(x))
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try:
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anagrams[x_tuple].append(x)
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except KeyError:
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anagrams[x_tuple] = [x]
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anagrams = [a for a in anagrams.values() if len(a) > 1]
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return anagrams
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def find_anagram_pairs(xs):
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anagrams = find_anagrams(xs)
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r = [pair
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for anagram in anagrams
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for pair in get_pair_subsets(anagram)]
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return r
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def words_match_numbers(words, numbers):
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letters_a, letters_b = words
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digits_a, digits_b = numbers
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digit_to_letter = {}
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for l, d in zip(letters_a, digits_a):
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if d in digit_to_letter and digit_to_letter[d] != l:
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# Each digit can only be assigned to one letter
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return False
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digit_to_letter[d] = l
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letter_to_digit = {l: d for l, d in zip(letters_a, digits_a)}
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for l, d in zip(letters_b, digits_b):
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if letter_to_digit[l] != d:
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return False
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return True
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def find_pairs(words, squares):
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pairs = []
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anagram_pairs = find_anagram_pairs(words)
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square_pairs = find_anagram_pairs(squares)
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for word_pair in anagram_pairs:
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for number_pair in square_pairs:
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if words_match_numbers(word_pair, number_pair):
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# pairs.append([word_pair, number_pair])
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pairs.append(number_pair)
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return pairs
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def euler_098():
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squares = [str(i * i) for i in range(200000)]
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words = get_words()
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largest_number = 0
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for i in range(3, 9):
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words_i = list(filter(lambda w: len(w) == i, words))
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squares_i = list(filter(lambda w: len(w) == i, squares))
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pairs = find_pairs(words_i, squares_i)
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for pair in pairs:
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n = max(map(int, pair))
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if n > largest_number:
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largest_number = n
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return largest_number
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if __name__ == "__main__":
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solution = euler_098()
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print("e098.py: " + str(solution))
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assert(solution == 18769)
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