백준 1620번(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));
		StringTokenizer st = new StringTokenizer(br.readLine());
		
		int N = Integer.parseInt(st.nextToken());
		int M = Integer.parseInt(st.nextToken());
		
		StringBuilder sb = new StringBuilder();
		
		HashMap<Integer, String> map1 = new HashMap<>();
		HashMap<String, Integer> map2 = new HashMap<>();
		
		for(int i=1; i<=N; i++) {
			String s = br.readLine();
			map1.put(i, s);
			map2.put(s, i);
		}
		
		for(int i=0; i<M; i++) {
			String s = br.readLine();
			
			if(s.charAt(0) >= 49 && s.charAt(0) <= 57) { // ascii 1~9
				sb.append(map1.get(Integer.parseInt(s))).append('\n');
			} else {
				sb.append(map2.get(s)).append('\n');
			}
		}
		System.out.println(sb);
	}
}