2185. Counting Words With a Given Prefix

Problem

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.

https://leetcode.com/problems/counting-words-with-a-given-prefix/

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 <= 100
1 <= words[i].length, pref.length <= 100
words[i] and pref consist of lowercase English letters.

Test Cases

1 2	class Solution: def prefixCount(self, words: List[str], pref: str) -> int:

solution_test.py

import pytest

from solution import Solution


@pytest.mark.parametrize('words, pref, expected', [
    (["pay","attention","practice","attend"], "at", 2),
    (["leetcode","win","loops","success"], "code", 0),
])
@pytest.mark.parametrize('sol', [Solution()])
def test_solution(sol, words, pref, expected):
    assert sol.prefixCount(words, pref) == expected

Thoughts

Code

solution.py

1
2
3

class Solution:
    def prefixCount(self, words: list[str], pref: str) -> int:
        return sum(1 for word in words if word.startswith(pref))

本文除了题目描述（Problem）部分之外，其他内容由 Calf 原创，采用 CC BY-NC-SA 4.0 许可协议，转载请注明出处。