Counting Words With a Given Prefix

main.md

Question

Approach

To solve the problem, I iterated directly over the list.Then I checked if the prefix pref matched the initial substring of the word. This was achieved by slicing the string word up to the length of pref and comparing it with pref. If they matched, I incremented a counter, which I returned at the end of the function.

Implemtation

class Solution:
    def prefixCount(self, words: List[str], pref: str) -> int:
        count = 0

        for word in words:
            if word[:len(pref)] == pref:
                count += 1
        return count

Complexities

• Time: O(n.m) where n is the number of strings in the words list and m is the length of the prefix pref.
• Space: O(1).