[알고리즘문제풀기] 중복된 문자 제거

문제

내가 작성한 정답

import java.util.*;
class Solution {
    public String solution(String my_string) {
        String answer = "";
        Set<String> set = new LinkedHashSet<>();
        for(String s : my_string.split("")){
            set.add(s);
        }
        return String.join("",set);
    }
}


class Solution {
    public String solution(String my_string) {
        String answer = "";
        for(String s:my_string.split("")){
            if(!answer.contains(s)){
                answer+=s;
            }
        }
        return answer;
    }
}

다른 사람들의 정답

import java.util.*;
class Solution {
    public String solution(String my_string) {
        String[] answer = my_string.split("");
        Set<String> set = new LinkedHashSet<String>(Arrays.asList(answer));

        return String.join("", set);
    }
}

import java.util.stream.Collectors;

class Solution {
    public String solution(String my_string) {
        return my_string.chars()
                .mapToObj(Character::toString)
                .distinct()
                .collect(Collectors.joining());
    }
}

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

        for(int i=0; i<my_string.length(); i++){
            //my_string.indexOf(my_string.charAt(i));
            if(i==my_string.indexOf(my_string.charAt(i)))
                answer+=my_string.charAt(i);
        }

        return answer;
    }
}