백준 1764번: 듣보잡 [자료구조][정렬][문자열] -Java

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

1764번: 듣보잡

백준 1764번: 듣보잡 [자료구조][정렬][문자열] -Java

import java.io.BufferedReader;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.Collections;
import java.util.HashMap;
import java.util.StringTokenizer;

public class Main {

	public static void main(String[] args) throws IOException {
		// TODO Auto-generated method stub
		
		//System.setIn(new FileInputStream("Test.txt"));
		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());
		
		HashMap<String, Integer> map = new HashMap<String, Integer>();
		
		for (int i = 0; i < N; i++) {
			st = new StringTokenizer(br.readLine());
			String key = st.nextToken();
			int cnt = 0;
			if(map.get(key)!=null)
				cnt = map.get(key);
			map.put(key, cnt+1);
		}
		for (int i = 0; i < M; i++) {
			st = new StringTokenizer(br.readLine());
			String key = st.nextToken();
			int cnt = 0;
			if(map.get(key)!=null)
				cnt = map.get(key);
			map.put(key, cnt+1);
		}
		
		
		ArrayList<String> list = new ArrayList<String>();
		for(String key : map.keySet()) {
			if(map.get(key)>1)
				list.add(key);
		}
		
		Collections.sort(list);
		
		System.out.println(list.size());
		for (int i = 0; i < list.size(); i++) {
			System.out.println(list.get(i));
		}
		
	}

}