6. 중복문자제거

import java.util.*;

class Main {
	public String solution(String str) {
		String answer = "";
		for (int i = 0; i < str.length(); i++) {
			if (!answer.contains(String.valueOf(str.charAt(i)))) {
				answer = answer.concat(String.valueOf(str.charAt(i)));
			}
		}
		return answer;
	}

	public static void main(String[] args) {
		Main T = new Main();
		Scanner kb = new Scanner(System.in);
		System.out.println(T.solution(kb.nextLine()));
	}
}

 

import java.util.*;

class Main {
	public String solution(String str) {
		String answer = "";
		for (int i = 0; i < str.length(); i++) {
		//	System.out.println(str.charAt(i) + " " + i + " "+str.indexOf(str.charAt(i)));
			if (str.indexOf(str.charAt(i)) == i)
				answer += str.charAt(i);
		}
		return answer;
	}

	public static void main(String[] args) {
		Main T = new Main();
		Scanner kb = new Scanner(System.in);
		System.out.println(T.solution(kb.nextLine()));
	}
}

answer += str.charAt(i);