2675번 '문자열 반복'

let input = Int(readLine()!)!
for _ in 1...input{
    let sentence = readLine()?.split(separator: " ")
    let repeatCount = Int((sentence?.first!.description)!)!
    let string = (sentence?.last!.description)!
    var result = ""
    for i in 0..<string.count{
        let char = string[string.index(string.startIndex, offsetBy: i)].description
        for _ in 0..<repeatCount{
            result += char
        }
    }
    print(result)
}