7 lines
207 B
Text
7 lines
207 B
Text
def fib_binet(n):
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(5|sqrt) as $rt
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| ((1 + $rt)/2) as $phi
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| (($phi | log) * n | exp) as $phin
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| (if 0 == (n % 2) then 1 else -1 end) as $sign
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| ( ($phin - ($sign / $phin) ) / $rt ) + .5
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| floor;
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