func binomial()

in Sources/Algorithms/Combinations.swift [68:75]

• 8 lines of code
• 4 McCabe index (conditional complexity)

    func binomial(n: Int, k: Int) -> Int {
      switch k {
      case n, 0: return 1
      case n...: return 0
      case (n / 2 + 1)...: return binomial(n: n, k: n - k)
      default: return n * binomial(n: n - 1, k: k - 1) / k
      }
    }