[Swift 알고리즘] 시저 암호

https://programmers.co.kr/learn/courses/30/lessons/12926

func solution(_ s:String, _ n:Int) -> String {

    var answer = ""

    for i in s {
        if i.isLetter{
            var value = (Int(i.asciiValue!)+n)
            if Int(i.asciiValue!) >= 65 && Int(i.asciiValue!) <= 90 {
                if value > 90 {
                    value = value - 26
                }
            } else {
                if value > 122 {
                    value = value - 26
                }
            }
            answer += String(UnicodeScalar(value)!)
        } else {
            answer += String(i)
        }


    }

    return answer
}

```