30 lines
622 B
Python
30 lines
622 B
Python
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from functools import cache
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def euler_092():
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count = 0
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square_dict = {str(i): i * i for i in range(10)}
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square_lookup = lambda s: square_dict[s]
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@cache
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def number_chain(n):
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if n == 1 or n == 89:
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return n
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squared_digits = map(square_lookup, str(n))
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new_n = sum(squared_digits)
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n = number_chain(new_n)
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return n
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for n in range(1, 10**7 + 1):
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if number_chain(n) == 89:
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count += 1
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return count
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if __name__ == "__main__":
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solution = euler_092()
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print("e092.py: " + str(solution))
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assert(solution == 8581146)
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