1684. 统计一致字符串的数目

1684. 统计一致字符串的数目

class Solution {
    public int countConsistentStrings(String allowed, String[] words) {
        int[] flag = new int[30];
        char[] all = allowed.toCharArray();
        for(int i = 0; i < all.length; i ++) {
            int index = all[i] - 'a';
            flag[index] = 1;
        }
        int res = 0;
        for(String word : words) {
            boolean f = true;
            for(int i = 0; i < word.length(); i ++) {
                int index = word.charAt(i)  - 'a';
                if(flag[index] != 1) {
                    f = false;
                    break;
                }
            }
            if(f) res ++;
        }
        return res;

    }
}