题解 | #删除字符串中出现次数最少的字符#

import java.util.Scanner;

// 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);
        String s = in.next();
        String[] s2 = new String[s.length()];
        String[] s1 = new String[s.length()];
        int max = 0;
        for (int i = 0 ; i < s.length(); i++) {
            s1[i] = s.substring(i, i + 1);
        }
        String res = null;
        int b = 0;
        for (int i = 0; i < s1.length; i++) {
            s2[i] = s.replace(s1[i], "");
            if (s2[i].length() > max) {
                max = s2[i].length();
                res = s2[i];
                b = i;
            } else if (s2[i].length() == max) {
                res = res.replace(s1[b], "");
                res = res.replace(s1[i], "");
                b = i;
            }
        }
        System.out.println(res);

    }
}