[백준] no11723: 집합

문제

 

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

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원리

들어온 커맨드에 따라 자료구조 메서드를 호출하면 된다.

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풀이방법

1. HashSet을 이용한 방법 - 2위

: 검색에 따라 더 빠르게 나오기도 한다.

 

2. ArrayList를 이용한 방법 - 1위

: 순서가 있어서 그런지 가장 빠르다

 

3. HashMap을 이용한 방법 - 3위

: 의외로 가장 느리다

 

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나의 코드

1. HashSet을 이용한 방법

import java.io.*;
import java.util.HashSet;
import java.util.Set;
import java.util.StringTokenizer;

public class no11723 {

    static Set<String> set = new HashSet<>();

    public static void main(String[] args) throws IOException {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(System.out));

        int T = Integer.parseInt(br.readLine());
        for (int i = 0; i < T; i++) {
            StringTokenizer st = new StringTokenizer(br.readLine(), " ");
            String cmd = st.nextToken();
              cmd = (cmd.equals("all") || cmd.equals("empty")) ? allOrEmpty(cmd) : calculate(cmd, st.nextToken(), bw);
        }
        bw.close();
    }

    private static String calculate(String cmd, String x, BufferedWriter bw) throws IOException {
        if (cmd.equals("add")) {
            if (!set.contains(x)) set.add(x);
        } else if (cmd.equals("remove")) {
            if (set.contains(x)) set.remove(x);
        } else if (cmd.equals("check")) {
            if (set.contains(x)) bw.append("1\n");
            else bw.append("0\n");
        } else if (cmd.equals("toggle")) {
            if (set.contains(x)) set.remove(x);
            else set.add(x);
        }
        return null;
    }

    private static String allOrEmpty(String cmd) throws IOException {
        if (cmd.equals("all")) {
            Set<String> newSet = new HashSet<>();
            for (int i = 1; i <= 20; i++) newSet.add(String.valueOf(i));
            set = newSet;
        } else if (cmd.equals("empty")) {
            set.clear();
        }
        return null;
    }
}

 

2. ArrayList를 이용한 방법

import java.io.*;
import java.util.*;

public class no11723 {

    static List<String> list = new ArrayList<>();

    public static void main(String[] args) throws IOException {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(System.out));

        int T = Integer.parseInt(br.readLine());
        for (int i = 0; i < T; i++) {
            StringTokenizer st = new StringTokenizer(br.readLine(), " ");
            String cmd = st.nextToken();
              cmd = (cmd.equals("all") || cmd.equals("empty")) ? allOrEmpty(cmd) : calculate(cmd, st.nextToken(), bw);
        }
        bw.close();
    }

    private static String calculate(String cmd, String x, BufferedWriter bw) throws IOException {
        if (cmd.equals("add")) {
            if (!list.contains(x)) list.add(x);
        } else if (cmd.equals("remove")) {
            if (list.contains(x)) list.remove(x);
        } else if (cmd.equals("check")) {
            if (list.contains(x)) bw.append("1\n");
            else bw.append("0\n");
        } else if (cmd.equals("toggle")) {
            if (list.contains(x)) list.remove(x);
            else list.add(x);
        }
        return null;
    }

    private static String allOrEmpty(String cmd) {
        if (cmd.equals("all")) {
            List<String> newList = new ArrayList<>();
            for (int i = 1; i <= 20; i++) newList.add(String.valueOf(i));
            list = newList;
        } else if (cmd.equals("empty")) {
            list.clear();
        }
        return null;
    }
}

 

3. HashMap을 이용한 방법

static Map<String, String> map = new HashMap();

public static void main(String[] args) throws IOException {
    BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
    BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(System.out));

    int T = Integer.parseInt(br.readLine());
    for (int i = 0; i < T; i++) {
        StringTokenizer st = new StringTokenizer(br.readLine(), " ");
        String cmd = st.nextToken();
          cmd = (cmd.equals("all") || cmd.equals("empty")) ? allOrEmpty(cmd) : calculate(cmd, st.nextToken(), bw);
    }
    bw.close();
}

private static String calculate(String cmd, String x, BufferedWriter bw) throws IOException {
    if (cmd.equals("add")) {
        if (!map.containsValue(x)) map.put(cmd+x, x);
    } else if (cmd.equals("remove")) {
        if (map.containsValue(x)) map.remove("add"+x);
    } else if (cmd.equals("check")) {
        if (map.containsValue(x)) bw.append("1\n");
        else bw.append("0\n");
    } else if (cmd.equals("toggle")) {
        if (map.containsValue(x)) map.remove("add"+x);
        else map.put("add"+x, x);
    }
    return null;
}

private static String allOrEmpty(String cmd) {
    if (cmd.equals("all")) {
        Map<String, String> newMap = new HashMap<>();
        for (int i = 1; i <= 20; i++) newMap.put("add"+i, String.valueOf(i));
        map = newMap;
    } else if (cmd.equals("empty")) {
        map.clear();
    }
    return null;
}