challenges-71.js

// #Question - Count the Number of Vowel Strings in Range

// You are given a 0-indexed array of string words and two integers left and right.

// A string is called a vowel string if it starts with a vowel character and ends with a vowel character where vowel characters are 'a', 'e', 'i', 'o', and 'u'.

// Return the number of vowel strings words[i] where i belongs to the inclusive range [left, right].

// Example 1:

// Input: words = ["are","amy","u"], left = 0, right = 2
// Output: 2
// Explanation:
// - "are" is a vowel string because it starts with 'a' and ends with 'e'.
// - "amy" is not a vowel string because it does not end with a vowel.
// - "u" is a vowel string because it starts with 'u' and ends with 'u'.
// The number of vowel strings in the mentioned range is 2.
// Example 2:

// Input: words = ["hey","aeo","mu","ooo","artro"], left = 1, right = 4
// Output: 3
// Explanation:
// - "aeo" is a vowel string because it starts with 'a' and ends with 'o'.
// - "mu" is not a vowel string because it does not start with a vowel.
// - "ooo" is a vowel string because it starts with 'o' and ends with 'o'.
// - "artro" is a vowel string because it starts with 'a' and ends with 'o'.
// The number of vowel strings in the mentioned range is 3.

// #Solution

var vowelStrings = function (words, left, right) {
  const vowelSet = new Set(["a", "e", "i", "o", "u"]);
  let count = 0;

  for (let i = left; i <= right; i++) {
    const word = words[i];
    if (vowelSet.has(word[0]) && vowelSet.has(word[word.length - 1])) {
      count++;
    }
  }

  return count;
};

vowelStrings(["are", "amy", "u"], 0, 2);