nth_catalan

Ali Hamdi Ali Fadel · @AliOsm · about 3 years

Calculates the n-th Catalan number, (2N)! / (N! * (N + 1)!), in a mathematical operations efficient way.


def nth_catalan(n)

  result = 1

  m = n + 2



  while m <= 2 * n do

    result = result * m / (m - n - 1)

    m += 1

  end



  result /= (m - n - 1)


end
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