Moved 20 to 26 to Python.
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f76b36c8d3
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@ -1,7 +1,11 @@
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from lib_misc import factorial
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def euler_020():
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return 0
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f_100 = factorial(100)
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return sum(map(int, str(f_100)))
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if __name__ == "__main__":
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assert(euler_020() == 1074)
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assert(euler_020() == 648)
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print("e020.py: {}".format(euler_020()))
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@ -0,0 +1,15 @@
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from lib_misc import sum_proper_divisors
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def euler_021():
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t = 0
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for n in range(1, 10000):
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s = sum_proper_divisors(n)
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if n != s and n == sum_proper_divisors(s):
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t += n
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return t
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if __name__ == "__main__":
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assert(euler_021() == 31626)
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print("e021.py: {}".format(euler_021()))
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@ -0,0 +1,17 @@
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def get_score_for_name(name):
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return sum([ord(c) - ord('A') + 1 for c in name if not c == '"'])
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def euler_022():
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with open('../txt/EulerProblem022.txt', 'r') as f:
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names = f.read().split(',')
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names.sort()
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s = sum([(i + 1) * get_score_for_name(name)
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for i, name in enumerate(names)])
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return s
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if __name__ == "__main__":
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assert(get_score_for_name('COLIN') == 53)
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assert(euler_022() == 871198282)
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print("e022.py: {}".format(euler_022()))
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@ -1,40 +1,28 @@
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import math
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def get_proper_divisors(n):
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proper_divisors = set([1])
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for i in range(2, int(math.sqrt(n)) + 1):
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if n % i == 0:
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proper_divisors.add(i)
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proper_divisors.add(n / i)
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return proper_divisors
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from lib_misc import sum_proper_divisors
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def is_abundant(n):
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return sum(get_proper_divisors(n)) > n
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return sum_proper_divisors(n) > n
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def get_abundant_numbers_smaller(n):
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ret = []
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for i in range(1, n):
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if is_abundant(i):
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ret.append(i)
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return ret
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def is_sum_of_two_abundant(n, abundant_numbers):
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abundant_numbers_set = set(abundant_numbers)
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for a1 in abundant_numbers:
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if a1 > n:
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def is_sum_of_two_abundant(n, abundant_numbers, abundant_numbers_set):
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for a in abundant_numbers:
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if a > n:
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return False
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elif (n - a1) in abundant_numbers_set:
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d = n - a
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if d in abundant_numbers_set:
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return True
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return False
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def euler_023():
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abundant_numbers = [n for n in range(1, 28123 + 1) if is_abundant(n)]
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abundant_numbers_set = set(abundant_numbers)
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return sum([n for n in range(1, 28123 + 1)
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if not is_sum_of_two_abundant(n, abundant_numbers,
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abundant_numbers_set)])
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if __name__ == "__main__":
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abundant_numbers = get_abundant_numbers_smaller(30000)
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cannot_be_written_as_sum_of_abundant = []
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for i in range(28129):
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if not is_sum_of_two_abundant(i, abundant_numbers):
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cannot_be_written_as_sum_of_abundant.append(i)
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print(sum(cannot_be_written_as_sum_of_abundant))
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print("e023.py: {}".format(euler_023()))
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assert(euler_023() == 4179871)
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@ -1,2 +1,31 @@
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from itertools import permutations
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print("".join(list(permutations("0123456789"))[1000000-1]))
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def euler_024_library():
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return int("".join(list(permutations("0123456789"))[1000000 - 1]))
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def permutations_(iterable):
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if not iterable:
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yield iterable
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for i in range(len(iterable)):
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elem = iterable[i:i + 1]
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rest = iterable[:i] + iterable[i + 1:]
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for ps in permutations_(rest):
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yield elem + ps
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def n_th(generator, n):
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for i in range(n):
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next(generator)
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return next(generator)
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def euler_024():
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g = permutations_("0123456789")
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return int(n_th(g, 1000000 - 1))
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if __name__ == "__main__":
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print("e024.py: {}".format(euler_024()))
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assert(euler_024() == 2783915460)
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113
python/e025.py
113
python/e025.py
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@ -1,109 +1,12 @@
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from copy import deepcopy
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from itertools import islice
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from lib_fibonacci import fibonacci_generator
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def primes(n):
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""" Nice way to calculate primes. Should be fast. """
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l = range(2, n + 1)
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_l = []
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while True:
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p = l[0]
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if p * p > n:
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return _l + l
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l = [i for i in l if i % p != 0]
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_l.append(p)
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def calculate_decimal_places(numerator, denominator):
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numerator = (numerator - (numerator / denominator) * denominator) * 10
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digits = []
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while True:
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digit = numerator / denominator
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numerator = (numerator - digit * denominator) * 10
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digits.append(digit)
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if digits[-3:] == [0, 0, 0]:
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raise StopIteration
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yield digit
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def has_cycle(decimal_places, n):
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d = decimal_places
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return list(islice(d, 0, n)) == list(islice(d, 0, n)) and \
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list(islice(d, 0, n)) == list(islice(d, 0, n))
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def f_025_1():
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""" Second try. I realized that only primes must be
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checked. Therefore, my brute force approach worked. """
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l = []
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for d in primes(1000):
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for i in range(5, 10000):
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decimal_places = calculate_decimal_places(1, d)
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if has_cycle(decimal_places, i):
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l.append((i, d))
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break
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print(max(l))
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def calculate_cycle(numerator, denominator):
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numerator = (numerator - (numerator / denominator) * denominator) * 10
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remainders = set([])
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while True:
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digit = numerator / denominator
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remainder = (numerator - digit * denominator)
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if remainder in remainders:
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raise StopIteration
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remainders.add(remainder)
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numerator = remainder * 10
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yield digit
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def f_025_2():
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""" Understood trick with remembering remainder... """
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s = [(len(list(calculate_cycle(1, d))), d)
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for d in range(1, 1001)]
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print(max(s))
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def f_025_3():
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""" Only testing primes... """
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s = [(len(list(calculate_cycle(1, d))), d)
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for d in primes(10000)]
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print(max(s))
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f_025_3()
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#print([(find_cycle_count(calculate_decimal_places(1, d)), d)
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# for d in range(1, 100)])
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#print(find_cycle_count(calculate_decimal_places(22, 7)))
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#l = []
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#for d in range(1, 1000):
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# for i in range(5, 1000):
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# decimal_places = calculate_decimal_places(1, d)
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# if has_cycle_one_off(decimal_places, i):
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# l.append((i, d))
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# break
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# decimal_places = calculate_decimal_places(1, d)
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# if has_cycle(decimal_places, i):
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# l.append((i, d))
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# break
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#def find_cycle_count(decimal_places):
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# cycles = []
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# for digit in decimal_places:
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# new_cycles = []
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# for cycle in cycles:
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# digits, length = cycle
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# if digits[0] == digit:
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# if len(digits[1:]) == 0:
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# return length
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# new_cycles.append((digits[1:], length))
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# new_cycles.append((digits + [digit], length + 1))
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# new_cycles.append(([digit], 1))
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# cycles = new_cycles
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def euler_025():
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for i, f in enumerate(fibonacci_generator()):
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if len(str(f)) >= 1000:
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return i + 1
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if __name__ == "__main__":
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print("e025.py: {}".format(euler_025()))
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assert(euler_025() == 4782)
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def primes(n):
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""" Nice way to calculate primes. Should be fast. """
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l = range(2, n + 1)
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_l = []
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while True:
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p = l[0]
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if p * p > n:
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return _l + l
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l = [i for i in l if i % p != 0]
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_l.append(p)
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from itertools import count
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def produce_prime(a, b, n, primes):
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x = n*n + a*n + b
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return x in primes
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def get_cycle_count(nominator, denominator):
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assert(nominator == 1)
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remainders = {}
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remainder = nominator
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results = []
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for i in count():
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result = remainder // denominator
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remainder = remainder % denominator
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results.append(result)
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if remainder in remainders:
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return i - remainders[remainder]
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else:
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remainders[remainder] = i
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if remainder == 0:
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return 0
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remainder *= 10
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def f_027():
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""" n^2 + a*n + b
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1) b must be prime
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"""
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p6 = set(primes(1000000))
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p3 = primes(1000)
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options = [(a, b)
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for a in range(1, 1000, 2)
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for b in p3]
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print(len(options))
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for n in range(100):
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options = [(a, b)
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for a, b in options
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if produce_prime(a, b, n, p6)]
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print(options)
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print(len(options))
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def euler_026():
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return max([(get_cycle_count(1, i), i) for i in range(1, 1000)])[1]
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f_027()
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if __name__ == "__main__":
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assert(get_cycle_count(1, 7) == 6)
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assert(get_cycle_count(1, 10) == 0)
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assert(get_cycle_count(1, 6) == 1)
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print("e026.py: {}".format(euler_026()))
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assert(euler_026() == 983)
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@ -134,4 +134,46 @@ def collatz_sequence_length(n):
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return length + collatz_sequence_length(n // 2)
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@lru_cache(maxsize=10000)
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def factorial(n):
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if n == 1:
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return 1
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return n * factorial(n - 1)
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def proper_divisors(n):
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"""
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Returns the list of divisors for n excluding n.
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"""
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if n < 2:
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return []
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divisors = [1, ]
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d = 2
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while d * d <= n:
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if n % d == 0:
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divisors.append(d)
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d += 1
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# Ignore first element and iterate list backwards.
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for d in divisors[1:][::-1]:
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q = n // d
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if q != d:
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divisors.append(q)
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return divisors
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def sum_proper_divisors(n):
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"""
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Returns the sum of proper divisors of a number.
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"""
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if n < 2:
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return 0
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s = 1
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d = 2
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while d * d <= n:
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if n % d == 0:
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s += d
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q = n // d
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if q != d:
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s += q
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d += 1
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return s
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@ -9,6 +9,8 @@ try:
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from .lib_misc import even, odd
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from .lib_misc import collatz_sequence
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from .lib_misc import collatz_sequence_length
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from .lib_misc import factorial
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from .lib_misc import proper_divisors, sum_proper_divisors
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except ModuleNotFoundError:
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from lib_misc import is_palindrome_integer
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from lib_misc import is_palindrome_string
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@ -19,6 +21,8 @@ except ModuleNotFoundError:
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from lib_misc import even, odd
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from lib_misc import collatz_sequence
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from lib_misc import collatz_sequence_length
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from lib_misc import factorial
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from lib_misc import proper_divisors, sum_proper_divisors
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class TestPrimeMethods(unittest.TestCase):
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[13, 40, 20, 10, 5, 16, 8, 4, 2, 1])
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self.assertEqual(collatz_sequence_length(13), 10)
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def test_factorial(self):
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self.assertEqual(factorial(1), 1)
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self.assertEqual(factorial(3), 6)
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self.assertEqual(factorial(10), 3628800)
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def test_proper_divisors(self):
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self.assertEqual(proper_divisors(0), [])
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self.assertEqual(proper_divisors(1), [])
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self.assertEqual(proper_divisors(2), [1])
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self.assertEqual(proper_divisors(4), [1, 2])
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self.assertEqual(proper_divisors(220), [
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1, 2, 4, 5, 10, 11, 20, 22, 44, 55, 110])
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def test_sum_proper_divisors(self):
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self.assertEqual(sum_proper_divisors(0), 0)
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self.assertEqual(sum_proper_divisors(1), 0)
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self.assertEqual(sum_proper_divisors(2), 1)
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self.assertEqual(sum_proper_divisors(3), 1)
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self.assertEqual(sum_proper_divisors(220), 284)
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self.assertEqual(sum_proper_divisors(284), 220)
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if __name__ == '__main__':
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unittest.main()
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@ -8,6 +8,8 @@ except ModuleNotFoundError:
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def prime_factors(n):
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"""
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Returns a list of prime factors for n.
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:param n: number for which prime factors should be returned
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"""
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# TODO: Look into using a prime wheel instead.
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def prime_factors_count(n):
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"""
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Returns a dictionay of primes where each key is a prime
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and the value how many times that prime is part of the factor of n.
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:param n: numober for which prime factor counts are returned
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:returns: a dict where they key is a prime vactor and the value
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the count of how of that value occurs
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:returns: a dict where they key is a prime and the value
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the count of how often that value occurs
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"""
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return get_item_counts(prime_factors(n))
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