25 lines
575 B
Nim
25 lines
575 B
Nim
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import math, sets
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iterator yellowstone(n: int): int =
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assert n >= 3
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for i in 1..3: yield i
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var present = [1, 2, 3].toHashSet
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var prevLast = 2
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var last = 3
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var start = 4
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for _ in 4..n:
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var candidate = start
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while true:
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if candidate notin present and gcd(candidate, last) == 1 and gcd(candidate, prevLast) != 1:
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yield candidate
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present.incl candidate
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prevLast = last
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last = candidate
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while start in present: inc start
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break
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inc candidate
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for n in yellowstone(30):
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stdout.write " ", n
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echo()
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