题解 | #删除字符串中出现次数最少的字符#

import java.util.*;

public class Main {

public Main() {
}

public String delete(String str) {
    // Map记录每个字母的次数
    Map<Character, Integer> map = new HashMap<>();
    for (char ch : str.toCharArray()) {
        map.put(ch, map.getOrDefault(ch, 0) + 1);
    }
    // 快速找出最少次数
    int min = Integer.MAX_VALUE;
    for (int times : map.values()) {
        min = Math.min(min, times);
    }
    StringBuilder res = new StringBuilder();
    for (char ch : str.toCharArray()) {
        if (map.get(ch) != min) {
            res.append(ch);
        }
    }
    return res.toString();
}

public static void main(String[] args) {
    Main solution = new Main();
    Scanner in = new Scanner(System.in);
    while (in.hasNextLine()) {
        String str = in.nextLine();
        String res = solution.delete(str);
        System.out.println(res);
    }
} 

}