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mike-burns/is_fib.rb

Created June 20, 2013 22:59
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Is a number in the set of Fibonacci numbers?
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is_fib.rb
module IsFibber
def fibonacci?(n)
perfect_square?(5 * n * n + 4) || perfect_square?(5 * n * n - 4)
end
private
def perfect_square?(f)
sqrt = Math.sqrt(f)
sqrt == sqrt.round
end
end
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