2185.js

/** ------------------------------------------------------------------------------
 * 
 * 2185. Counting Words With a Given Prefix
 * Topics: Array, String
 * https://leetcode.com/problems/counting-words-with-a-given-prefix/?envType=daily-question&envId=2025-01-09
 * 
 ------------------------------------------------------------------------------ */
/**
 * @param {string[]} words
 * @param {string} pref
 * @return {number}
 */
var prefixCount = function (words, pref) {
  return words.filter((w) => w.startsWith(pref)).length
}

/**
 * 5초풀이에서 공간복잡도 줄이기
 */
var prefixCount = function (words, pref) {
  let answer = 0
  for (let word of words) {
    if (word.startsWith(pref)) {
      answer++
    }
  }
  return answer
}

/**
 * 가장 최적화
 */
var prefixCount = function (words, pref) {
  let count = 0
  for (let i = 0; i < words.length; i++) {
    if (words[i].indexOf(pref) === 0) count++
  }
  return count
}

console.log(prefixCount(["pay", "attention", "practice", "attend"], "at"))