You are given an array of strings words and a string pref.
Return the number of strings in words that contain pref as a prefix.
A prefix of a string s is any leading contiguous substring of s.
Example 1:
Input: words = ["pay","attention","practice","attend"], pref = "at"
Output: 2
Explanation: The 2 strings that contain "at" as a prefix are: "attention" and "attend".
Example 2:
Input: words = ["leetcode","win","loops","success"], pref = "code"
Output: 0
Explanation: There are no strings that contain "code" as a prefix.
Constraints:
1 <= words.length <= 1001 <= words[i].length, pref.length <= 100words[i] and pref consist of lowercase English letters.