[BOJ] 11723 집합 (JAVA)

https://www.acmicpc.net/problem/11723

11723번: 집합

비트마스킹으로 풀면 실행시간이 조금 더 빠를 겁니다.

 

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.util.HashSet;
import java.util.StringTokenizer;

public class Main {
	
    static BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
    static StringBuilder sb = new StringBuilder();
    static StringTokenizer st;
    static int M, x;
    static String input;

    public static void main(String[] args) throws Exception {

        HashSet<Integer> set = new HashSet<>();
        M = Integer.parseInt(br.readLine());
        for (int i = 0; i < M; i++) {
            st = new StringTokenizer(br.readLine(), " ");
            input = st.nextToken();
            if ("add".equals(input)) {
                set.add(Integer.parseInt(st.nextToken()));
            } else if ("remove".equals(input)) {
                set.remove(Integer.parseInt(st.nextToken()));
            } else if ("check".equals(input)) {
                sb.append(set.contains(Integer.parseInt(st.nextToken())) ? 1 : 0).append("\n");
            } else if ("toggle".equals(input)) {
                x = Integer.parseInt(st.nextToken());
                if (set.contains(x)) set.remove(x);
                else set.add(x);
            } else if ("all".equals(input)) {
                for (int j = 1; j <= 20; j++) {
                    set.add(j);
                }
            } else set.clear();
        }

        System.out.print(sb);

    }

}