영어 끝말잇기

def solution(n, words):
    answer = [] 
    wordSet = set()  
    wordSet.add(words[0])  
    
    for k in range(1, len(words)):
        #row int division
        #col remainder 
        i = (k % n) + 1  #1 based 
        j = (k // n) + 1  
        
        if words[k] in wordSet:
            return [i, j] 
        
        if words[k][0] != words[k-1][-1]:
            return [i, j] 
        
        wordSet.add(words[k])
    
    return [0, 0]