[Java] 6. 중복문자제거

중복제거에는 역시 Set..!

         * hashSet = 순서 없이 리스트에 담는 방법
         * linkedHashSet = 넣는 순서대로 리스트에 담는 방법
         * treeSet = 넣는 값을 기준으로 오름차순으로 정렬하여 담는 방법

package review;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.HashSet;
import java.util.LinkedHashSet;
import java.util.Set;

public class Main {
    public String solution(String str) {
        /**
         * hashSet = 순서 없이 리스트에 담는 방법
         * linkedHashSet = 넣는 순서대로 리스트에 담는 방법
         * treeSet = 넣는 값을 기준으로 오름차순으로 정렬하여 담는 방법
         */

        String answer = "";
        char[] chars = str.toCharArray();
        Set<Character> set = new LinkedHashSet<>();

        for(char x : chars) {
            set.add(x);
        }
        StringBuilder sb = new StringBuilder();
        for(char x :set) {
            sb.append(x);
        }
        answer = sb.toString();

        return answer;
    }

    public static void main(String[] args) throws IOException{
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        String str = br.readLine();
        Main main = new Main();
        System.out.println(main.solution(str));
    }
}

package review;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;


public class String06 {
    // input : ksekkset, output : kset
    public static void main(String[] args) throws IOException {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        String str = br.readLine();
        String06 string06 = new String06();
        System.out.println(string06.solution(str));
    }

    public String solution(String str) {
        String answer = "";

        for ( int i = 0; i < str.length(); i++){
            System.out.println("i : " +i +
                    " str.indexOf(i) : " +str.indexOf(i) +
                    " str.charAt(i) : "+ str.charAt(i) +
                    " str.indexOf(str.charAt(i)) == i : " + (str.indexOf(str.charAt(i)) == i) +
                    " str.indexOf(str.charAt(i) : " + (str.indexOf(str.charAt(i))));
            if ( str.indexOf(str.charAt(i)) == i) {
                answer += str.charAt(i);
            }
        }

        return answer;
    }
}

// i, str.indexOf, str.charAt, str.indexOf(str.charAt(i)) 차이

i : 0 str.indexOf(i) : -1 str.charAt(i) : k str.indexOf(str.charAt(i)) == i : true str.indexOf(str.charAt(i) : 0
i : 1 str.indexOf(i) : -1 str.charAt(i) : s str.indexOf(str.charAt(i)) == i : true str.indexOf(str.charAt(i) : 1
i : 2 str.indexOf(i) : -1 str.charAt(i) : e str.indexOf(str.charAt(i)) == i : true str.indexOf(str.charAt(i) : 2
i : 3 str.indexOf(i) : -1 str.charAt(i) : k str.indexOf(str.charAt(i)) == i : false str.indexOf(str.charAt(i) : 0
i : 4 str.indexOf(i) : -1 str.charAt(i) : k str.indexOf(str.charAt(i)) == i : false str.indexOf(str.charAt(i) : 0
i : 5 str.indexOf(i) : -1 str.charAt(i) : s str.indexOf(str.charAt(i)) == i : false str.indexOf(str.charAt(i) : 1
i : 6 str.indexOf(i) : -1 str.charAt(i) : e str.indexOf(str.charAt(i)) == i : false str.indexOf(str.charAt(i) : 2
i : 7 str.indexOf(i) : -1 str.charAt(i) : t str.indexOf(str.charAt(i)) == i : true str.indexOf(str.charAt(i) : 7

package review;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.List;


public class String06 {
    // input : ksekkset, output : kset
    public static void main(String[] args) throws IOException {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        String str = br.readLine();
        String06 string06 = new String06();
        System.out.println(string06.solution(str));
    }

    public String solution(String str) {
        StringBuilder answer = new StringBuilder();

        List<Character> list = new ArrayList<>();
        for ( char ch : str.toCharArray()) {
            if(!list.contains(ch)) {
                list.add(ch);
                answer.append(ch);
            }
        }
        return answer.toString();
    }
}