[프로그래머스][Level1] 신규 아이디 추천 c++

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

프로그래머스

 

풀이과정

문제가 길어 당황할 수 있지만, 단계별로 해나가면 풀 수 있는 문제이다.  
단계를 보면 문자를 제거하라는 조건이 있는데 여기서 공백으로 치환해줬다.  
공백으로 치환해줬으면 erase와 remove 함수를 써서 지워줘야 한다.

 

#include <string>
#include <vector>
#include <algorithm>

using namespace std;

string solution(string new_id) {
    string answer = "";

    // 1단계
    for(int i = 0; i < new_id.size(); i++){
        if('A' <= new_id[i] && new_id[i] <= 'Z') new_id[i] += 32;
    }
    // 2단계
    for(int i = 0; i < new_id.size(); i++){
        if('a' <= new_id[i] && new_id[i] <= 'z' || '0' <= new_id[i] && new_id[i] <= '9')
            continue;
        if(new_id[i] == '-' || new_id[i] == '_' || new_id[i] == '.')
            continue;
        new_id[i] = ' ';
    }
    new_id.erase(remove(new_id.begin(), new_id.end(), ' '), new_id.end());

    // 3단계
    for(int i = 0; i < new_id.size() - 1; i++){
        if(new_id[i] == '.'){
            while(new_id[i + 1] == '.'){
                new_id[i + 1] = ' ';
                i++;
            }
        }
    }
    new_id.erase(remove(new_id.begin(), new_id.end(), ' '), new_id.end());

    // 4단계
    if(new_id[0] == '.') new_id[0] = ' ';
    if(new_id[new_id.size() - 1] == '.') new_id[new_id.size() - 1] = ' ';
    new_id.erase(remove(new_id.begin(), new_id.end(), ' '), new_id.end());

    // 5단계
    if(new_id.size() == 0) new_id += "a";

    // 6단계
    if(new_id.size() >= 16){
        for(int i = 15; i < new_id.size(); i++){
            new_id[i] = ' ';
        }
        if(new_id[14] == '.') new_id[14] = ' ';
    }
    new_id.erase(remove(new_id.begin(), new_id.end(), ' '), new_id.end());

    // 7단계
    if(new_id.size() <= 2){
        char c = new_id[new_id.size() - 1];
        while(new_id.size() <= 2){
            new_id += c;
        }
    }
    answer = new_id;
    return answer;
}