题解 | 计算某字符出现次数

import java.util.Scanner;
import java.util.Map;
import java.util.HashMap;

public class Main {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        String str = in.nextLine().toLowerCase();
        String c = in.nextLine().toLowerCase();
        Map<Character, Integer> map = new HashMap<>();
        for(char ch : str.toCharArray()) {
            if(map.containsKey(ch)) {
                map.put(ch, map.get(ch)+1);
            } else {
                map.put(ch, 1);
            }
        }
        if(map.containsKey(c.charAt(0))) {
            System.out.println(map.get(c.charAt(0)));
        } else {
            System.out.println(0);
        }
        

    }
}