README_CN.md

1684. 统计一致字符串的数目

给你一个由不同字符组成的字符串 allowed 和一个字符串数组 words 。如果一个字符串的每一个字符都在 allowed 中，就称这个字符串是 一致字符串 。

请你返回 words 数组中 一致字符串 的数目。

示例 1:

输入: allowed = "ab", words = ["ad","bd","aaab","baa","badab"]
输出: 2
解释: 字符串 "aaab" 和 "baa" 都是一致字符串，因为它们只包含字符 'a' 和 'b' 。

示例 2:

输入: allowed = "abc", words = ["a","b","c","ab","ac","bc","abc"]
输出: 7
解释: 所有字符串都是一致的。

示例 3:

输入: allowed = "cad", words = ["cc","acd","b","ba","bac","bad","ac","d"]
输出: 4
解释: 字符串 "cc"，"acd"，"ac" 和 "d" 是一致字符串。

提示:

• 1 <= words.length <= 104
• 1 <= allowed.length <= 26
• 1 <= words[i].length <= 10
• allowed 中的字符 互不相同 。
• words[i] 和 allowed 只包含小写英文字母。

题解 (Rust)

1. 题解

impl Solution {
    pub fn count_consistent_strings(allowed: String, words: Vec<String>) -> i32 {
        let allowed = allowed.bytes().fold(0, |ac, c| ac | (1 << (c - b'a')));

        words
            .iter()
            .filter(|word| word.bytes().all(|c| allowed & (1 << (c - b'a')) != 0))
            .count() as i32
    }
}