45 lines
957 B
Python
45 lines
957 B
Python
from math import sqrt
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# O(√n)
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def isPrime(n):
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if n < 2: return False
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if n == 2 or n == 3 or n == 5: return True
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limit = int(sqrt(n))
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numberToCheck = 5
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while numberToCheck <= limit:
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if n % numberToCheck == 0: return False
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numberToCheck += 2 # Skip all even numbers
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return True
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# Would be O(log₂(n)), but isPrime(n) is used,
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# thus it's O(√n)
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def findAllFactors(n):
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factors = []
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while not isPrime(n):
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for i in range(2, int(n)):
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if n % i == 0:
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factors.append(i)
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n = n / i
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break
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factors.append(int(n))
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return factors
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def factorize(n):
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factors = []
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if isPrime(n):
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factors.append(n)
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else:
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factors = findAllFactors(n)
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return factors
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if __name__ == "__main__":
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n = int(input('Skriv inn et positivt heltall: '))
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factors = factorize(n)
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if len(factors) == 1:
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print(f'{n} er et primtall')
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else:
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print(f'{n} = {" * ".join([str(tall) for tall in factorize(n)])}') |