문제 링크https://school.programmers.co.kr/learn/courses/30/lessons/120888 KeyStringBuilderHashSetcontains() 제출한 코드import java.util.*;class Solution { public String solution(String my_string) { Set mySet = new HashSet(); StringBuilder builder = new StringBuilder(); for(char c : my_string.toCharArray()){ if(mySet.contains(c)) continue; mySet.add(c)..
