39 lines
822 B
Python
39 lines
822 B
Python
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from functools import lru_cache
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@lru_cache
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def count(days_left, absent_count):
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if absent_count > 1:
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return 0
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if days_left == 0:
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return 1
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if days_left < 0:
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return 0
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c = 0
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c += count(days_left - 1, absent_count + 1) # "a"
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c += count(days_left - 2, absent_count + 1) # "la"
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c += count(days_left - 3, absent_count + 1) # "lla"
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c += count(days_left - 1, absent_count) # "o"
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c += count(days_left - 2, absent_count) # "lo"
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c += count(days_left - 3, absent_count) # "llo"
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if days_left == 2:
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c += 1 # "ll"
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if days_left == 1:
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c += 1 # "l"
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return c
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def euler_191():
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return count(30, 0)
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if __name__ == "__main__":
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solution = euler_191()
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print("e191.py: " + str(solution))
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assert(solution == 1918080160)
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