백준1157: 단어 공부

문제

https://www.acmicpc.net/problem/1157

문제 풀이

import java.util.*;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        HashMap<Character, Integer> map = new HashMap<>();
        ArrayList<Character> list = new ArrayList<>();

        String word = sc.next().toUpperCase();
        int max = 0;

        for (int i = 0; i < word.length(); i++) {
            char c = word.charAt(i);
            map.put(c, map.getOrDefault(c, 0) + 1);
            max = Math.max(max, map.get(c));
        }

        for (Map.Entry<Character, Integer> entry : map.entrySet()) {
            if (entry.getValue() == max) {
                list.add(entry.getKey());
            }
        }

        System.out.println(list.size()>1 ? "?" : list.get(0));
    }
}