mirror of
https://github.com/TheAlgorithms/Python.git
synced 2024-10-07 06:09:28 +00:00
51 lines
1.4 KiB
Python
51 lines
1.4 KiB
Python
"""
|
|
The nth term of the sequence of triangle numbers is given by, tn = ½n(n+1); so
|
|
the first ten triangle numbers are:
|
|
|
|
1, 3, 6, 10, 15, 21, 28, 36, 45, 55, ...
|
|
|
|
By converting each letter in a word to a number corresponding to its
|
|
alphabetical position and adding these values we form a word value. For example,
|
|
the word value for SKY is 19 + 11 + 25 = 55 = t10. If the word value is a
|
|
triangle number then we shall call the word a triangle word.
|
|
|
|
Using words.txt (right click and 'Save Link/Target As...'), a 16K text file
|
|
containing nearly two-thousand common English words, how many are triangle
|
|
words?
|
|
"""
|
|
import os
|
|
|
|
|
|
# Precomputes a list of the 100 first triangular numbers
|
|
TRIANGULAR_NUMBERS = [int(0.5 * n * (n + 1)) for n in range(1, 101)]
|
|
|
|
|
|
def solution():
|
|
"""
|
|
Finds the amount of triangular words in the words file.
|
|
|
|
>>> solution()
|
|
162
|
|
"""
|
|
script_dir = os.path.dirname(os.path.realpath(__file__))
|
|
wordsFilePath = os.path.join(script_dir, 'words.txt')
|
|
|
|
words = ''
|
|
with open(wordsFilePath, 'r') as f:
|
|
words = f.readline()
|
|
|
|
words = list(map(lambda word: word.strip('"'), words.strip('\r\n').split(',')))
|
|
words = list(
|
|
filter(
|
|
lambda word: word in TRIANGULAR_NUMBERS,
|
|
map(
|
|
lambda word: sum(map(lambda x: ord(x) - 64, word)),
|
|
words
|
|
)
|
|
)
|
|
)
|
|
return len(words)
|
|
|
|
if __name__ == '__main__':
|
|
print(solution())
|