2018-12-05 15:22:54 +10:30
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import numpy as np
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max_it = 813960 # Somewhat cheaty - this value was obtained from an earlier factor-based brute force. Just use an arbitrarily large number if it fails.
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input = 33100000
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houses = np.ones([max_it], dtype=np.int64)
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pres10 = input//10
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for i in range(2, max_it):
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houses[i::i] += i
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print(np.argmax(houses > pres10)) # Part 1
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houses_2 = np.ones([max_it], dtype=np.int64)
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pres11 = input//11
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for i in range(2, max_it):
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houses_2[i:i*51:i] += i
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print(np.argmax(houses_2 > pres11)) # Part 2
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