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939811371e
Eclipse integration for simpler use with Windows. Still have to perform some good work on prime numbers! Signed-off-by: Julien Lengrand-Lambert <julien@lengrand.fr>
100 lines
2.6 KiB
Python
100 lines
2.6 KiB
Python
#!/usr/bin/env python
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'''
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Created on 7 feb. 2012
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@author: Julien Lengrand-Lambert
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DESCRIPTION: Solves problem 42 of Project Euler
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The nth term of the sequence of triangle numbers is given by, t_n = 1/2 * n * (n+1);
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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
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to its alphabetical position and adding these values we form a word value.
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For example, the word value for SKY is 19 + 11 + 25 = 55 = t_10.
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If the word value is a triangle number then we shall call the word a triangle word.
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Using e_42.data (right click and 'Save Link/Target As...'),
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a 16K text file containing nearly two-thousand common English words,
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how many are triangle words?
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'''
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import string
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def load_data(filename):
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"""
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Loads the data from a name file into a table
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"""
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my_file = open(filename, "r")
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line = my_file.readline()
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data = [el for el in line.split("\"")][1::2]
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my_file.close()
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return data
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def dict_alphabet():
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"""
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Returns a dict of the alphabet, with value for each letter.
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"""
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alpb= dict()
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letters = string.ascii_uppercase
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inc = 1
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for j in range(len(letters)):
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alpb[letters[j]] = inc
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inc += 1
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return alpb
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def names2scores(data):
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"""
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Returns a list of scores given a list of names.
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Scores are calculated with word values, (A = 1, B = 2, ...)
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"""
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scores = []
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alpb = dict_alphabet()
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for name in data:
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score = 0
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for jj in range(len(name)):
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score += (alpb[name[jj]])
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scores.append(score)
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return scores
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def triangle_list(max_val):
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"""
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Returns a list of triangle numbers up to max_val.
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triangle_numbers is an increasing function.
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"""
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trilist = []
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ptr = 1
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val = 1
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while val < max_val:
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val = trinum(ptr)
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trilist.append(val)
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ptr += 1
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return trilist
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def trinum(val):
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"""
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Returns the triangle number for a given value
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"""
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return val * (val + 1) / 2
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def triangle_words(filename):
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"""
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Returns the number of triangle words in filename
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"""
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data = load_data(filename)
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scores = names2scores(data)
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trilist = triangle_list(max(scores))
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# checking if words are triangle
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cpt = 0
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for score in scores:
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if score in trilist:
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cpt += 1
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return cpt
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if __name__ == '__main__':
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print "Answer : %d " % (triangle_words("e_42.data")) |