영어 끝말잇기

function solution(n, words) { let answer = [0, 0]; let exist = {}; let prevLetter = words[0].slice(-1); exist[words[0]] = true; for (let i = 1; i < words.length; i++) { if (prevLetter !== words[i][0] || exist[words[i]]) { answer = [i % n + 1, parseInt(i / n) + 1]; break; } prevLetter = words[i].slice(-1); exist[words[i]] = true; } return answer; }