영어 끝말잇기

import java.util.*;

class Solution {
    public int[] solution(int n, String[] words) {
        int[] answer = {};

        HashSet<String> hash = new HashSet<>();
        
        int who = -1;
        int count = -1;
        char prev = words[0].charAt(0);
        for(int i = 0; i < words.length; ++i)
        {
            String cur = words[i];
            if(false == hash.contains(cur) && prev == cur.charAt(0))
            {
                hash.add(cur);
                prev = cur.charAt(cur.length()-1);
            }               
            else
            {
                who = i%n;
                count = i/n;
                break;
            }  
        }

        answer = new int[2];
        answer[0] = who+1;
        answer[1] = count+1;
        return answer;
    }
}