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1961. Check If String Is a Prefix of Array

Difficulty Topics

Description

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

check-if-string-is-a-prefix-of-array.py
class Solution:
    def isPrefixString(self, s: str, words: List[str]) -> bool:
        res = ""

        for word in words:
            res += word

            if res == s: return True

        return False