풀이
import java.util.*;
class Solution {
public String solution(String new_id) {
String a = "";
new_id = new_id.toLowerCase(); //1단계
for (int i = 0; i < new_id.length(); i++) {
char c = new_id.charAt(i);
if ((c >= 'a' && c <= 'z') || (c >= '0' && c <= '9') || c == '-' || c == '_' || c == '.') {
a += c;
}
} //2단계
while (a.contains(".."))
{
a = a.replace("..", ".");
} //3단계
if (a.length() > 0 && a.charAt(0) == '.')
{
a = a.substring(1);
} //4단계
if (a.length() > 0 && a.charAt(a.length() - 1) == '.') {
a = a.substring(0, a.length() - 1);
} //4단계 추가작업
if (a.equals("")) {
a = "a";
} //5단계
if (a.length() >= 16) {
a = a.substring(0, 15);
if (a.charAt(a.length()-1) == '.') {
a = a.substring(0, a.length()-1);
}
} //6단계
while (a.length() <= 2) {
a += a.charAt(a.length() - 1);
} //7단계
return a;
}
}