题解 | #计算某字母出现次数#

import java.util.*;
public class Main{
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        String s1 = sc.nextLine();
        String ss1 = sc.nextLine();
        String s2 = s1.toUpperCase();
        String ss2 = ss1.toUpperCase();
        Map<Character, Integer> map = new HashMap<>();
        for(int i=0;i<s2.length();i++){
            if(map.containsKey(s2.charAt(i))){
                map.put(s2.charAt(i),map.get(s2.charAt(i))+1);
            }else{
                map.put(s2.charAt(i),1);
            }
        }
        Set<Map.Entry<Character, Integer>> set = map.entrySet();
        Iterator<Map.Entry<Character, Integer>> it = set.iterator();
        while (it.hasNext()) {
            Map.Entry<Character, Integer> entry = it.next();
            String key=entry.getKey()+"";
            Integer val = entry.getValue();
            if (ss2.equals(key)) {
                System.out.println(val);
                return;
            }
        }
        System.out.println(0);
    }
}