1 题目

2 代码

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

public class B1039 {
    public static void main(String[] args) throws Exception {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        char[] input = br.readLine().toCharArray();
        char[] res = br.readLine().toCharArray();

        int[] hash = new int[123];
        for (int i = 0; i < input.length; i++) {
            hash[input[i]]++;
        }
        Set<Character> set = new HashSet<Character>();
        for (int i = 0; i < res.length; i++) {
            set.add(res[i]);
            hash[res[i]]--;
        }

        int num = 0;
        Iterator<Character> iterator = set.iterator();
        while (iterator.hasNext()) {
            int index = iterator.next();
            if (hash[index] < 0)
                num += Math.abs(hash[index]);
        }

        if (num == 0)
            System.out.println("Yes " + (input.length - res.length));
        else
            System.out.println("No " + num);
    }
}

3 要点

（1）利用Hash表保存两个字符串中字符的个数，如果后续num大于0，说明缺少珠子；反之，可以购买，两个字符串长度相减即可。