[BaekJoon] 1764번 듣보잡 문제 풀이 (Success)

1764번: 듣보잡

 

☕Language: Java

 

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.util.HashSet;
import java.util.Set;
import java.util.StringTokenizer;
import java.util.TreeSet;
 
public class Main {
 
    public static void main(String[] args) throws IOException {
        BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(System.out));
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
 
        StringTokenizer st = new StringTokenizer(br.readLine());
 
        int N = Integer.parseInt(st.nextToken());
        int M = Integer.parseInt(st.nextToken());
 
        Set<String> set = new HashSet<>();
        for (int i = 0; i < N; i++) {
            set.add(br.readLine());
        }
 
        int cnt = 0;
        Set<String> result = new TreeSet<>();
        while (M-- > 0) {
            String s = br.readLine();
            if (set.contains(s)) {
                cnt++;
                result.add(s);
            }
        }
 
        bw.write(cnt + "\n");
        for(String s : result) {
            bw.write(s+"\n");
        }
 
        bw.flush();
        bw.close();
 
    }
 
}
 

🤔 해설

1. Set<String> set = new HashSet<>();

   - 들은 적 없는 사람을 set에 저장

 

2. if (set.contains(s)) { ... }

    - 본적도 없는 사람이 set(들은 적 없는 사람)에 존재 할 경우,

        - cnt + 1 && result에 추가

    - Set<String> result = new TreeSet<>();

        - 사전순 정렬을 위해 Treeset 활용

 

😮 이 외의 풀이

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.util.HashMap;
import java.util.Map;
import java.util.Set;
import java.util.StringTokenizer;
import java.util.TreeSet;
 
public class Main {
    public static void main(String[] args) throws IOException {
        BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(System.out));
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
 
        StringTokenizer st = new StringTokenizer(br.readLine());
 
        int N = Integer.parseInt(st.nextToken());
        int M = Integer.parseInt(st.nextToken());
 
        Map<String, Boolean> map = new HashMap<>();
 
        for (int i = 0; i < N; i++) {
            map.put(br.readLine(), false);
        }
 
        while (M-- > 0) {
            String s = br.readLine();
            if (map.containsKey(s)) {
                map.replace(s, true);
            }
        }
 
        Set<String> set = new TreeSet<>();
 
        for (String s : map.keySet()) {
            if (map.get(s)) {
                set.add(s);
            }
        }
 
        StringBuilder sb = new StringBuilder();
        
        sb.append(set.size()).append("\n");
        
        for (String s : set) {
            sb.append(s).append("\n");
        }
 
        bw.write(sb.toString());
 
        bw.flush();
        bw.close();
    }
}
 

- HashMap + TreeSet 사용

 

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.util.ArrayList;
import java.util.Collections;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.StringTokenizer;
import java.util.TreeSet;
 
public class Main {
    public static void main(String[] args) throws IOException {
        BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(System.out));
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
 
        StringTokenizer st = new StringTokenizer(br.readLine());
 
        int N = Integer.parseInt(st.nextToken());
        int M = Integer.parseInt(st.nextToken());
 
        Map<String, Boolean> map = new HashMap<>();
 
        for (int i = 0; i < N; i++) {
            map.put(br.readLine(), false);
        }
 
        while (M-- > 0) {
            String s = br.readLine();
            if (map.containsKey(s)) {
                map.put(s, true);
            }
        }
 
        List<String> list = new ArrayList<>();
 
        for (String s : map.keySet()) {
            if (map.get(s)) {
                list.add(s);
            }
        }
 
        StringBuilder sb = new StringBuilder();
 
        sb.append(list.size()).append("\n");
 
        Collections.sort(list);
 
        for (String s : list) {
            sb.append(s).append("\n");
        }
 
        bw.write(sb.toString());
 
        bw.flush();
        bw.close();
    }
}
 

- HashMap + ArrayList 사용

 

 

 

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