题解 | #计算某字符出现次数#

import java.util.*;

public class Main{
    public static void main(String[] args){
        Scanner sc = new Scanner(System.in);
        String str = sc.nextLine();
        str = str.toUpperCase();
        String c = sc.nextLine();
        c = c.toUpperCase();
        String[] arr = str.split("");
        HashMap<String,Integer> hashMap = new HashMap<>();
        for(int i = 0 ; i<arr.length ; i++){
            Integer count = hashMap.get(arr[i]);
            if(count == null){
                count = 1;
            }else{
                count += 1;
            }
            hashMap.put(arr[i],count);
        }
        Integer out = hashMap.get(c);
        if(out == null){
            out = 0;
        }
        System.out.println(out);
    }
}