[프로그래머스] 핸드폰 번호 가리기(Java)

 

 

 

 

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나의 풀이

class Solution {
    public String solution(String phone_number) {
        String answer = "";
        String front = phone_number.substring(0, phone_number.length()-4);
        String back = phone_number.substring(phone_number.length()-4, phone_number.length());
        String[] frontList = new String[front.length()];
        for(int i = 0; i < front.length(); i++){
            frontList[i] = "*";
        }
        front = String.join("", frontList);
        answer = front + back;
        
        return answer;
    }
}

 

String.join()

String result = String.join(delimiter, elements);

 

 

 

 

 

 

다른 사람의 풀이 1

class Solution {
  public String solution(String phone_number) {
     char[] ch = phone_number.toCharArray();
     for(int i = 0; i < ch.length - 4; i ++){
         ch[i] = '*';
     }
     return String.valueOf(ch);
  }
}

 

 

 

다른 사람의 풀이 2

class Solution {
  public String solution(String phone_number) {
      String answer = "";

        for (int i = 0; i < phone_number.length() - 4; i++)
            answer += "*";

        answer += phone_number.substring(phone_number.length() - 4);

        return answer;
  }
}