신규 아이디 추천

신규 아이디 추천
2021 KAKAO BLIND RECRUITMENT 
4526명 완료

programmers.co.kr/learn/courses/30/lessons/72410

코딩테스트 연습 - 신규 아이디 추천

파이썬

정규표현식은 매번 쓰려면 리마인드가 안되서 간단하게... 

def solution(new_id: str) -> str:
    new_id = new_id.lower()
    answer = ''
    for each in new_id:
        if each in 'abcdefghijklmnopqrstuvwxyz-_.1234567890':
            answer += each
    while '..' in answer:
        answer = answer.replace('..', '.')
    if len(answer) > 0 and answer[0] == '.':
        answer = answer[1:]
    if len(answer) > 0 and answer[-1] == '.':
        answer = answer[:-1]
    if len(answer) == 0:
        answer = 'a'
    if len(answer) >= 16:
        answer = answer[:15]
        if answer[-1] == '.':
            answer = answer[:-1]
    while len(answer) <= 2:
        answer += answer[-1]
    return answer

좀 더 정리한다면?

def solution(new_id: str) -> str:
    new_id = new_id.lower()
    answer = ''
    for each in new_id:
        if each in 'abcdefghijklmnopqrstuvwxyz-_.1234567890':
            answer += each
    while '..' in answer:
        answer = answer.replace('..', '.')
    if answer and answer[0] == '.':
        answer = answer[1:]
    if answer and answer[-1] == '.':
        answer = answer[:-1]
    if not answer:
        answer = 'a'
    if len(answer) >= 16:
        answer = answer[:15]
        if answer[-1] == '.':
            answer = answer[:-1]
    while len(answer) <= 2:
        answer += answer[-1]
    return answer

 

Java

자바에서 직접 문자열 처리하는 것 보다는
정규표현식이 편한 것 같습니다. 

class Solution {
    public String solution(String new_id) {
        new_id = new_id.toLowerCase();
        new_id = new_id.replaceAll("[^\\w-._]+", "");
        new_id = new_id.replaceAll("\\.+", ".");
        new_id = new_id.replaceAll("(^\\.)|(\\.$)", "");
        if (new_id.length() == 0) new_id = "a";
        if (new_id.length() >= 16) new_id = new_id.substring(0, 15);
        new_id = new_id.replaceAll("\\.$", "");
        while (new_id.length() <= 2) new_id += new_id.charAt(new_id.length() - 1);
        return new_id;
    }
}