69 lines
1.3 KiB
Python
Executable File
69 lines
1.3 KiB
Python
Executable File
#!/usr/bin/env python
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# Problem 3:
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#
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# The prime factors of 13195
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# are 5, 7, 13 and 29.
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#
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# What is the largest prime
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# factor of the number 600851475143 ?
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#
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import decorators
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import time
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# Create function that finds the next
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# prime number when supplied with an
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# intitial integer.
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def primes_gen(start_n,max_n):
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"""
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Returns a generator object, containing the
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primes inside a specified range.
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primes_gen(start_n,max_n)
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param 'start_n': Previous prime.
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param 'max_n': Maximum
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"""
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start_n += 1
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for candidate in range(start_n,max_n):
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notPrime = False
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if candidate in [0,1,2,3]:
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yield candidate
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for dividend in range(2,candidate):
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if candidate%dividend == 0:
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notPrime = True
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if not notPrime:
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yield candidate
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@decorators.function_timer
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def main():
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orig = 600851475143
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result1 = orig
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prime_start = 2
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returned_prime = prime_start
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prime_factor_list = []
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while returned_prime < orig ** 0.5 and returned_prime<result1:
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returned_prime = primes_gen(prime_start,orig).__next__()
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result2 = result1/returned_prime
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if result1%returned_prime == 0:
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#print(" {} / {} = {}".format(result1,returned_prime,result2))
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prime_factor_list.append(returned_prime)
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result1 = result2
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prime_start = returned_prime
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print("This highest prime factor of {} is {} ... ".format(orig,max(prime_factor_list)))
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main() |