题解 | #删除字符串中出现次数最少的字符#

import java.util.*;

// 注意类名必须为 Main, 不要有任何 package xxx 信息
public class Main {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        while (in.hasNextLine()) {
            String sinput = in.nextLine();
            Map<String, Integer> map = new HashMap<>(sinput.length());
            char[] arr = sinput.toCharArray();
            for (char ch : arr) {
                map.put(String.valueOf(ch),
                        map.get(String.valueOf(ch)) == null ? 1 : map.get(String.valueOf(ch)) + 1);
            }
            //System.out.println(map);
            Collection<Integer> c = map.values();
            Integer i = Collections.min(c);
            for (Map.Entry<String, Integer> e : map.entrySet()) {
                if (i == e.getValue()) {
                    sinput = sinput.replaceAll(e.getKey(), "");
                }
            }
            System.out.println(sinput);
        }
    }
}