题解 | #计算某字符出现次数#

import java.util.*;
public class Main{
    public static void main(String[] args){
        Scanner in = new Scanner(System.in);
        while(in.hasNext()){
            String str = in.nextLine().toLowerCase();
            String s = in.nextLine().toLowerCase();
            HashMap<Character,Integer> map = new HashMap<>();
            for(char ss:str.toCharArray()){
                if(ss==s.charAt(0)){
                    map.put(ss,map.getOrDefault(ss,0)+1);
                }
            }
            int len = (map.get(s.charAt(0))==null ? 0:map.get(s.charAt(0)));
            System.out.println(len);
        }
    }
}