57 lines
1.4 KiB
Python
57 lines
1.4 KiB
Python
#!/usr/bin/env python
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"""
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Created on 26 Jul 2021
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@author: David Doblas Jiménez
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@email: daviddoji@pm.me
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Solution for problem 042 of Project Euler
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https://projecteuler.net/problem=42
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"""
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from pathlib import Path
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from utils import timeit
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def triangle_number(num):
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return int(0.5 * num * (num + 1))
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def word_to_value(word):
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return sum(ord(letter) - 64 for letter in word)
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@timeit("Problem 042")
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def compute():
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"""
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The nth term of the sequence of triangle numbers is given by,
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tn = n(n+1)/2; so the first ten triangle numbers are:
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1, 3, 6, 10, 15, 21, 28, 36, 45, 55, ...
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By converting each letter in a word to a number corresponding to its
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alphabetical position and adding these values we form a word value. For
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example, the word value for SKY is 19 + 11 + 25 = 55 = t10. If the word
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value is a triangle number then we shall call the word a triangle word.
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Using words.txt, a 16K text file containing nearly two-thousand common
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English words, how many are triangle words?
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"""
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triangular_numbers = [triangle_number(n) for n in range(27)]
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ans = 0
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file = Path("files/Problem42.txt")
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with open(file, "r") as f:
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words = f.readline().strip('"').split('","')
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for word in words:
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if word_to_value(word) in triangular_numbers:
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ans += 1
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return ans
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if __name__ == "__main__":
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print(f"Result for Problem 042: {compute()}")
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