nayuki/Project-Euler-solutions

Switch branches/tags
Nothing to show
ec93b13 Dec 27, 2016
1 contributor

Users who have contributed to this file

54 lines (40 sloc) 1.34 KB
 # # Solution to Project Euler problem 79 # Copyright (c) Project Nayuki. All rights reserved. # # https://www.nayuki.io/page/project-euler-solutions # https://github.com/nayuki/Project-Euler-solutions # import itertools def compute(): # Only guess characters that appear in the attempts charsused = sorted(set().union(*SUBSEQS)) base = len(charsused) # Try ascending lengths for length in itertools.count(base): indices = [0] * length while True: guess = "".join(charsused[d] for d in indices) if is_consistent(guess): return guess # Increment indices i = 0 while i < length and indices[i] == base - 1: indices[i] = 0 i += 1 if i == length: break indices[i] += 1 def is_consistent(guess): return all(is_subsequence(s, guess) for s in SUBSEQS) def is_subsequence(shortstr, longstr): i = 0 for c in longstr: if c == shortstr[i]: i += 1 if i == len(shortstr): return True return False SUBSEQS = ["319", "680", "180", "690", "129", "620", "762", "689", "762", "318", "368", "710", "720", "710", "629", "168", "160", "689", "716", "731", "736", "729", "316", "729", "729", "710", "769", "290", "719", "680", "318", "389", "162", "289", "162", "718", "729", "319", "790", "680", "890", "362", "319", "760", "316", "729", "380", "319", "728", "716"] if __name__ == "__main__": print(compute())