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34 lines
932 B
Python
Executable File
34 lines
932 B
Python
Executable File
#!/usr/bin/env python
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"""
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#---
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Julien Lengrand-Lambert
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Created on : Wed Jan 11 14:42:54 CET 2012
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DESCRIPTION : Solves problem 3 of Project Euler
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The prime factors of 13195 are 5, 7, 13 and 29.
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What is the largest prime factor of the number 600851475143 ?
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#---
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"""
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def largest_prime_factor(value):
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"""
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Returns the largest prime factor of value
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"""
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max_match = pow(value, 0.5) + 1
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curr_prime = 2
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rest = value
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fin_prime = curr_prime
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while (curr_prime <= max_match or curr_prime < rest):
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if (rest % curr_prime == 0):
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fin_prime = curr_prime
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while (rest % curr_prime == 0):
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rest = rest / curr_prime
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curr_prime += 1
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if (curr_prime % 1000000 == 0):
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print "%d / %d / %d" % (curr_prime, rest, max_match)
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return fin_prime
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if __name__ == '__main__':
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val = 600851475143
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print "Answer : %d " % (largest_prime_factor(val))
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