[Swift] 영어 끝말잇기

func solution(_ n:Int, _ words:[String]) -> [Int] {
    for i in 1..<words.count {
        if (words[i-1].last != words[i].first) || (words[0..<i].contains(words[i])){
            return [i % n + 1, i / n + 1]
        }
    }
    return [0,0]
}