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Codewars.swift

/*
    DISCLAIMER
    ==========
    
    I do not own or have created the snippets below.
    I'm including them here for my own reference and knowledge improvement.
*/

//Triangular

func triangular(_ n: Int) -> Int{
    return stride(from: 1, through: n, by: 1).reduce(0, +)
}

func triangular(_ n: Int) -> Int{
  guard n > 0 else {
    return 0
  }
  return n+triangular(n-1)
}

func triangular(_ n: Int) -> Int{
 return n > 0 ? (1...n).reduce(0,+) : 0
}

//Disemvowel

func disemvowel(_ s: String) -> String {
  return s.replacingOccurrences(of: "[aeiou]", with: "", options: [.regularExpression, .caseInsensitive])
}

func disemvowel(_ s: String) -> String {
  let vowels: [Character] = ["a", "e", "i", "o", "u", "A", "E", "I", "O", "U"]
  
  return String(s.characters.filter { !vowels.contains($0) })
}

func disemvowel(_ s: String) -> String {
  return s.components(separatedBy: CharacterSet(charactersIn: "aeiouAEIOU")).joined()
}

func disemvowel(_ s: String) -> String {
  return s.map{ "\($0)" }.filter{ !("ieaou".contains($0.lowercased())) }.joined()
}

func disemvowel(_ s: String) -> String {
    return s.filter { !"aeiouAEIOU".contains($0) }
}

//Which are in
func inArray(_ a1: [String], _ a2: [String]) -> [String] {
    return Set(a1.filter { s1 in a2.contains { $0.contains(s1) } }).sorted()
}