백준 10816번(Java)

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));
		
		// key:입력되는 값, value:key의 개수
		HashMap<Integer, Integer> map = new HashMap<Integer,Integer>();
		
		int N = Integer.parseInt(br.readLine());
		StringTokenizer st = new StringTokenizer(br.readLine()," ");
		
		for(int i=0; i<N; i++) {
			int key = Integer.parseInt(st.nextToken());
			
			// getOrDefault(key, defaultValue)
			// key가 있으면 value, 없으면 defaultValue
			map.put(key, map.getOrDefault(key, 0)+1);
		}
		
		int M = Integer.parseInt(br.readLine());
		StringBuilder sb = new StringBuilder();
		st = new StringTokenizer(br.readLine()," ");
		
		for(int i=0; i<M; i++) {
			int key = Integer.parseInt(st.nextToken());
			
			sb.append(map.getOrDefault(key, 0)).append(' ');
		}
		System.out.println(sb);
	}
}