题解 | #汽水瓶#

import Foundation

while let line = readLine() {
       
    let number = Int(line)!
    //! 0 不输出
    if (number == 0) {
        continue
    }
    let count = help(number)

    print(String(count))


    // let parts = line.split(separator: " ")
    // print(Int(parts[0])! + Int(parts[1])!)
}


//! 关键递归函数
func help(_ number:Int) -> Int {
      if (number == 0 || number == 1) {
        return 0
      } else if (number == 2 || number == 3) {
        return 1
      }

      let count = number / 3

      return count + help(count + number % 3)

}