Moved 20 to 26 to Python.

main
Felix Martin 2019-07-15 22:11:49 -04:00
parent 0ab214633e
commit f76b36c8d3
10 changed files with 194 additions and 174 deletions

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@ -1,7 +1,11 @@
from lib_misc import factorial
def euler_020():
return 0
f_100 = factorial(100)
return sum(map(int, str(f_100)))
if __name__ == "__main__":
assert(euler_020() == 1074)
assert(euler_020() == 648)
print("e020.py: {}".format(euler_020()))

15
python/e021.py Normal file
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@ -0,0 +1,15 @@
from lib_misc import sum_proper_divisors
def euler_021():
t = 0
for n in range(1, 10000):
s = sum_proper_divisors(n)
if n != s and n == sum_proper_divisors(s):
t += n
return t
if __name__ == "__main__":
assert(euler_021() == 31626)
print("e021.py: {}".format(euler_021()))

17
python/e022.py Normal file
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@ -0,0 +1,17 @@
def get_score_for_name(name):
return sum([ord(c) - ord('A') + 1 for c in name if not c == '"'])
def euler_022():
with open('../txt/EulerProblem022.txt', 'r') as f:
names = f.read().split(',')
names.sort()
s = sum([(i + 1) * get_score_for_name(name)
for i, name in enumerate(names)])
return s
if __name__ == "__main__":
assert(get_score_for_name('COLIN') == 53)
assert(euler_022() == 871198282)
print("e022.py: {}".format(euler_022()))

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@ -1,40 +1,28 @@
import math
def get_proper_divisors(n):
proper_divisors = set([1])
for i in range(2, int(math.sqrt(n)) + 1):
if n % i == 0:
proper_divisors.add(i)
proper_divisors.add(n / i)
return proper_divisors
from lib_misc import sum_proper_divisors
def is_abundant(n):
return sum(get_proper_divisors(n)) > n
return sum_proper_divisors(n) > n
def get_abundant_numbers_smaller(n):
ret = []
for i in range(1, n):
if is_abundant(i):
ret.append(i)
return ret
def is_sum_of_two_abundant(n, abundant_numbers):
abundant_numbers_set = set(abundant_numbers)
for a1 in abundant_numbers:
if a1 > n:
def is_sum_of_two_abundant(n, abundant_numbers, abundant_numbers_set):
for a in abundant_numbers:
if a > n:
return False
elif (n - a1) in abundant_numbers_set:
d = n - a
if d in abundant_numbers_set:
return True
return False
def euler_023():
abundant_numbers = [n for n in range(1, 28123 + 1) if is_abundant(n)]
abundant_numbers_set = set(abundant_numbers)
return sum([n for n in range(1, 28123 + 1)
if not is_sum_of_two_abundant(n, abundant_numbers,
abundant_numbers_set)])
if __name__ == "__main__":
abundant_numbers = get_abundant_numbers_smaller(30000)
cannot_be_written_as_sum_of_abundant = []
for i in range(28129):
if not is_sum_of_two_abundant(i, abundant_numbers):
cannot_be_written_as_sum_of_abundant.append(i)
print(sum(cannot_be_written_as_sum_of_abundant))
print("e023.py: {}".format(euler_023()))
assert(euler_023() == 4179871)

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@ -1,2 +1,31 @@
from itertools import permutations
print("".join(list(permutations("0123456789"))[1000000-1]))
def euler_024_library():
return int("".join(list(permutations("0123456789"))[1000000 - 1]))
def permutations_(iterable):
if not iterable:
yield iterable
for i in range(len(iterable)):
elem = iterable[i:i + 1]
rest = iterable[:i] + iterable[i + 1:]
for ps in permutations_(rest):
yield elem + ps
def n_th(generator, n):
for i in range(n):
next(generator)
return next(generator)
def euler_024():
g = permutations_("0123456789")
return int(n_th(g, 1000000 - 1))
if __name__ == "__main__":
print("e024.py: {}".format(euler_024()))
assert(euler_024() == 2783915460)

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@ -1,109 +1,12 @@
from copy import deepcopy
from itertools import islice
from lib_fibonacci import fibonacci_generator
def primes(n):
""" Nice way to calculate primes. Should be fast. """
l = range(2, n + 1)
_l = []
while True:
p = l[0]
if p * p > n:
return _l + l
l = [i for i in l if i % p != 0]
_l.append(p)
def calculate_decimal_places(numerator, denominator):
numerator = (numerator - (numerator / denominator) * denominator) * 10
digits = []
while True:
digit = numerator / denominator
numerator = (numerator - digit * denominator) * 10
digits.append(digit)
if digits[-3:] == [0, 0, 0]:
raise StopIteration
yield digit
def has_cycle(decimal_places, n):
d = decimal_places
return list(islice(d, 0, n)) == list(islice(d, 0, n)) and \
list(islice(d, 0, n)) == list(islice(d, 0, n))
def f_025_1():
""" Second try. I realized that only primes must be
checked. Therefore, my brute force approach worked. """
l = []
for d in primes(1000):
for i in range(5, 10000):
decimal_places = calculate_decimal_places(1, d)
if has_cycle(decimal_places, i):
l.append((i, d))
break
print(max(l))
def calculate_cycle(numerator, denominator):
numerator = (numerator - (numerator / denominator) * denominator) * 10
remainders = set([])
while True:
digit = numerator / denominator
remainder = (numerator - digit * denominator)
if remainder in remainders:
raise StopIteration
remainders.add(remainder)
numerator = remainder * 10
yield digit
def f_025_2():
""" Understood trick with remembering remainder... """
s = [(len(list(calculate_cycle(1, d))), d)
for d in range(1, 1001)]
print(max(s))
def f_025_3():
""" Only testing primes... """
s = [(len(list(calculate_cycle(1, d))), d)
for d in primes(10000)]
print(max(s))
f_025_3()
#print([(find_cycle_count(calculate_decimal_places(1, d)), d)
# for d in range(1, 100)])
#print(find_cycle_count(calculate_decimal_places(22, 7)))
#l = []
#for d in range(1, 1000):
# for i in range(5, 1000):
# decimal_places = calculate_decimal_places(1, d)
# if has_cycle_one_off(decimal_places, i):
# l.append((i, d))
# break
# decimal_places = calculate_decimal_places(1, d)
# if has_cycle(decimal_places, i):
# l.append((i, d))
# break
#def find_cycle_count(decimal_places):
# cycles = []
# for digit in decimal_places:
# new_cycles = []
# for cycle in cycles:
# digits, length = cycle
# if digits[0] == digit:
# if len(digits[1:]) == 0:
# return length
# new_cycles.append((digits[1:], length))
# new_cycles.append((digits + [digit], length + 1))
# new_cycles.append(([digit], 1))
# cycles = new_cycles
def euler_025():
for i, f in enumerate(fibonacci_generator()):
if len(str(f)) >= 1000:
return i + 1
if __name__ == "__main__":
print("e025.py: {}".format(euler_025()))
assert(euler_025() == 4782)

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@ -1,38 +1,31 @@
def primes(n):
""" Nice way to calculate primes. Should be fast. """
l = range(2, n + 1)
_l = []
while True:
p = l[0]
if p * p > n:
return _l + l
l = [i for i in l if i % p != 0]
_l.append(p)
from itertools import count
def produce_prime(a, b, n, primes):
x = n*n + a*n + b
return x in primes
def get_cycle_count(nominator, denominator):
assert(nominator == 1)
remainders = {}
remainder = nominator
results = []
for i in count():
result = remainder // denominator
remainder = remainder % denominator
results.append(result)
if remainder in remainders:
return i - remainders[remainder]
else:
remainders[remainder] = i
if remainder == 0:
return 0
remainder *= 10
def f_027():
""" n^2 + a*n + b
1) b must be prime
"""
p6 = set(primes(1000000))
p3 = primes(1000)
options = [(a, b)
for a in range(1, 1000, 2)
for b in p3]
print(len(options))
for n in range(100):
options = [(a, b)
for a, b in options
if produce_prime(a, b, n, p6)]
print(options)
print(len(options))
def euler_026():
return max([(get_cycle_count(1, i), i) for i in range(1, 1000)])[1]
f_027()
if __name__ == "__main__":
assert(get_cycle_count(1, 7) == 6)
assert(get_cycle_count(1, 10) == 0)
assert(get_cycle_count(1, 6) == 1)
print("e026.py: {}".format(euler_026()))
assert(euler_026() == 983)

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@ -134,4 +134,46 @@ def collatz_sequence_length(n):
return length + collatz_sequence_length(n // 2)
@lru_cache(maxsize=10000)
def factorial(n):
if n == 1:
return 1
return n * factorial(n - 1)
def proper_divisors(n):
"""
Returns the list of divisors for n excluding n.
"""
if n < 2:
return []
divisors = [1, ]
d = 2
while d * d <= n:
if n % d == 0:
divisors.append(d)
d += 1
# Ignore first element and iterate list backwards.
for d in divisors[1:][::-1]:
q = n // d
if q != d:
divisors.append(q)
return divisors
def sum_proper_divisors(n):
"""
Returns the sum of proper divisors of a number.
"""
if n < 2:
return 0
s = 1
d = 2
while d * d <= n:
if n % d == 0:
s += d
q = n // d
if q != d:
s += q
d += 1
return s

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@ -9,6 +9,8 @@ try:
from .lib_misc import even, odd
from .lib_misc import collatz_sequence
from .lib_misc import collatz_sequence_length
from .lib_misc import factorial
from .lib_misc import proper_divisors, sum_proper_divisors
except ModuleNotFoundError:
from lib_misc import is_palindrome_integer
from lib_misc import is_palindrome_string
@ -19,6 +21,8 @@ except ModuleNotFoundError:
from lib_misc import even, odd
from lib_misc import collatz_sequence
from lib_misc import collatz_sequence_length
from lib_misc import factorial
from lib_misc import proper_divisors, sum_proper_divisors
class TestPrimeMethods(unittest.TestCase):
@ -70,6 +74,27 @@ class TestPrimeMethods(unittest.TestCase):
[13, 40, 20, 10, 5, 16, 8, 4, 2, 1])
self.assertEqual(collatz_sequence_length(13), 10)
def test_factorial(self):
self.assertEqual(factorial(1), 1)
self.assertEqual(factorial(3), 6)
self.assertEqual(factorial(10), 3628800)
def test_proper_divisors(self):
self.assertEqual(proper_divisors(0), [])
self.assertEqual(proper_divisors(1), [])
self.assertEqual(proper_divisors(2), [1])
self.assertEqual(proper_divisors(4), [1, 2])
self.assertEqual(proper_divisors(220), [
1, 2, 4, 5, 10, 11, 20, 22, 44, 55, 110])
def test_sum_proper_divisors(self):
self.assertEqual(sum_proper_divisors(0), 0)
self.assertEqual(sum_proper_divisors(1), 0)
self.assertEqual(sum_proper_divisors(2), 1)
self.assertEqual(sum_proper_divisors(3), 1)
self.assertEqual(sum_proper_divisors(220), 284)
self.assertEqual(sum_proper_divisors(284), 220)
if __name__ == '__main__':
unittest.main()

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@ -8,6 +8,8 @@ except ModuleNotFoundError:
def prime_factors(n):
"""
Returns a list of prime factors for n.
:param n: number for which prime factors should be returned
"""
# TODO: Look into using a prime wheel instead.
@ -30,10 +32,12 @@ def prime_factors(n):
def prime_factors_count(n):
"""
Returns a dictionay of primes where each key is a prime
and the value how many times that prime is part of the factor of n.
:param n: numober for which prime factor counts are returned
:returns: a dict where they key is a prime vactor and the value
the count of how of that value occurs
:returns: a dict where they key is a prime and the value
the count of how often that value occurs
"""
return get_item_counts(prime_factors(n))