2185. Counting Words With a Given Prefix

Description

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

 

Solutions

Solution: Brute Force

• Time complexity: O(n*pref.length)
• Space complexity: O(1)

 

JavaScript

/**
 * @param {string[]} words
 * @param {string} pref
 * @return {number}
 */
const prefixCount = function (words, pref) {
  let result = 0;

  for (const word of words) {
    if (word.startsWith(pref)) {
      result += 1;
    }
  }
  return result;
};