Fibonacci Sequence

Mix.install([
  {:jason, "~> 1.4"},
  {:kino, "~> 0.9", override: true},
  {:youtube, github: "brooklinjazz/youtube"},
  {:hidden_cell, github: "brooklinjazz/hidden_cell"},
  {:benchee, "~> 1.1"}
])

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Fibonacci Sequence

The Fibonacci Sequence is a series of the following numbers.

flowchart LR
a[0] --> b[1] --> c[1] --> d[2] --> e[3] --> f[5] --> g[8] --> h[13] --> i[21] --> k[34] --> ...

It’s created by taking the sum of the previous to numbers to get the next number.

So $fib(n) = fib(n-1) + fib(n - 2)$

You’ll notice that this is a recursive function. You’re going to create a Fibonacci module that can generate the $nth$ fibonacci number.

Example Solution

defmodule Fibonacci do
  def of(0), do: 0
  def of(1), do: 1

  def of(n) do
    of(n - 1) + of(n - 2)
  end
end

Implement the Fibonacci module as documented.

defmodule Fibonacci do
  @moduledoc """
  Documentation for the `Fibonacci` module.
  """

  @doc """
  Generate the nth fibonacci number.

  ## Examples

    iex> Fibonacci.of(0)
    0

    iex> Fibonacci.of(1)
    1

    iex> Fibonacci.of(2)
    1

    iex> Fibonacci.of(3)
    2

    iex> Fibonacci.of(4)
    3

    iex> Fibonacci.of(5)
    5

    iex> Fibonacci.of(6)
    8

    iex> Fibonacci.of(20)
    6765
  """
  def of(n) do
  end
end

Commit Your Progress

DockYard Academy now recommends you use the latest Release rather than forking or cloning our repository.

Run git status to ensure there are no undesirable changes. Then run the following in your command line from the curriculum folder to commit your progress.

$ git add .
$ git commit -m "finish Fibonacci Sequence exercise"
$ git push

We’re proud to offer our open-source curriculum free of charge for anyone to learn from at their own pace.

We also offer a paid course where you can learn from an instructor alongside a cohort of your peers. We will accept applications for the June-August 2023 cohort soon.

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