import Foundation

func validBraces(_ string:String) -> Bool {
  var check = [Character]()
  
  for char in string {
  
    switch char {
      case "(", "[", "{":
        check.append(char)
      case ")":
        if let last = check.last, last == "(" {
          check.removeLast()
        } else {
          return false
        }
      case "]":
        if let last = check.last, last == "[" {
          check.removeLast()
        } else {
          return false
        }
      case "}":
        if let last = check.last, last == "{" {
          check.removeLast()
        } else {
          return false
        }
      default: break
    }
  }
  return (check.count == 0) ? true : false
}