Two Sum

S1

defmodule Solution do
  @spec two_sum(nums :: [integer], target :: integer) :: [integer]
  def two_sum(nums, target) do
    for {x, i} <- Enum.with_index(nums),
        {y, j} <- Enum.with_index(Enum.drop(nums, i + 1), i + 1),
        x + y == target do
      [i, j]
    end
    |> Enum.at(0)
  end
end

ExUnit.start(autorun: false)

defmodule Test do
  use ExUnit.Case

  test nil do
    assert Solution.two_sum([2, 7, 11, 15], 9) == [0, 1]
    assert Solution.two_sum([3, 2, 4], 6) == [1, 2]
    assert Solution.two_sum([3, 3], 6) == [0, 1]
  end
end

ExUnit.run()