public class Solution
extends Object
1961 - Check If String Is a Prefix of Array\.
Easy
Given a string `s` and an array of strings `words`, determine whether `s` is a **prefix string** of `words`.
A string `s` is a **prefix string** of `words` if `s` can be made by concatenating the first `k` strings in `words` for some **positive** `k` no larger than `words.length`.
Return `true` _if_ `s` _is a **prefix string** of_ `words`_, or_ `false` _otherwise_.
**Example 1:**
**Input:** s = "iloveleetcode", words = ["i","love","leetcode","apples"]
**Output:** true
**Explanation:** s can be made by concatenating "i", "love", and "leetcode" together.
**Example 2:**
**Input:** s = "iloveleetcode", words = ["apples","i","love","leetcode"]
**Output:** false
**Explanation:** It is impossible to make s using a prefix of arr.
**Constraints:**
* `1 <= words.length <= 100`
* `1 <= words[i].length <= 20`
* `1 <= s.length <= 1000`
* `words[i]` and `s` consist of only lowercase English letters.