231225 자동완성

public int solution(String[] words) {
	List<String> sortedWords = Arrays.asList(words);
	Collections.sort(sortedWords);

	int answer = commonPrefixLength(sortedWords.get(0), sortedWords.get(1));
	answer += (answer < sortedWords.get(0).length()) ? 1 : 0;

	for (int i = 1; i < sortedWords.size() - 1; i++) {
		int prevLen = commonPrefixLength(sortedWords.get(i), sortedWords.get(i - 1));
		int nextLen = commonPrefixLength(sortedWords.get(i), sortedWords.get(i + 1));
		int maxLength = Math.max(prevLen, nextLen);

		answer += (maxLength < sortedWords.get(i).length()) ? 1 : 0;
		answer += maxLength;
	}

	int lastLen = commonPrefixLength(sortedWords.get(sortedWords.size() - 2),
			sortedWords.get(sortedWords.size() - 1));
	answer += (lastLen < sortedWords.get(sortedWords.size() - 1).length()) ? 1 : 0;

	return answer + lastLen;
}

private int commonPrefixLength(String s1, String s2) {
	int length = 0;
	int minLength = Math.min(s1.length(), s2.length());

	for (int i = 0; i < minLength; i++) {
		if (s1.charAt(i) == s2.charAt(i)) {
			length++;
		} else {
			break;
		}
	}

	return length;
}

출처:https://school.programmers.co.kr/learn/courses/30/lessons/17685