[백준-1764번/Java] 듣보잡

https://www.acmicpc.net/problem/1764

1764번: 듣보잡

 

* Map을 이용해서 풀었다.

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

public class Main {

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

		int N = Integer.parseInt(stk.nextToken());
		int M = Integer.parseInt(stk.nextToken());

		Map<String, Integer> unheard = new HashMap<String, Integer>();
		Map<String, Integer> unseen = new HashMap<String, Integer>();

		for (int i = 0; i < N; i++) {
			unheard.put(br.readLine(), i);
		}

		for (int i = 0; i < M; i++) {
			unseen.put(br.readLine(), i);
		}

		ArrayList<String> common = new ArrayList<String>();


		if (N > M) {
			Object[] arr = unseen.keySet().toArray();
			for (Object string : arr) {
				if (unheard.get(string) != null) {

					common.add((String) string);
				}
			}
		} else {
			Object[] arr = unheard.keySet().toArray();
			for (Object string : arr) {
				if (unseen.get(string) != null) {
					common.add((String) string);
				} else {
				}
			}
		}
		Collections.sort(common);
		
		System.out.println(common.size());
		for (String string : common) {
			System.out.println(string);
		}
	}

}