[BOJ] 1159 농구 경기 (JAVA)

https://www.acmicpc.net/problem/1159

1159번: 농구 경기

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.util.*;

public class Main {
	
    public static void main(String[] args) throws Exception {

        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        StringBuilder sb = new StringBuilder();
        int N = Integer.parseInt(br.readLine());
        Map<Character, Integer> map = new HashMap<>();
        for (int i = 0; i < N; i++) {
            char c = br.readLine().charAt(0);
            map.put(c, map.getOrDefault(c, 0) + 1);
        }

        List<Character> list = new ArrayList<>();
        map.entrySet().forEach(x -> {
            if (5 <= x.getValue()) list.add(x.getKey());
        });

        Collections.sort(list);

        for (Character c : list) {
            sb.append(c);
        }

        if (list.isEmpty()) System.out.print("PREDAJA");
        else System.out.print(sb);

    }

}