1961. Check If String Is a Prefix of Array

#### QUESTION:

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.
``````

#### SOLUTION:

``````class Solution {
func isPrefixString(_ s: String, _ words: [String]) -> Bool {
var tmpString = ""
for word in words {
tmpString += word
if !s.hasPrefix(tmpString) {
return false
}
if s == tmpString {
return true
}
}
return false
}
}
``````