2586. Count the Number of Vowel Strings in Range LeetCode Solution

In this guide, you will get 2586. Count the Number of Vowel Strings in Range LeetCode Solution with the best time and space complexity. The solution to Count the Number of Vowel Strings in Range problem is provided in various programming languages like C++, Java, and Python. This will be helpful for you if you are preparing for placements, hackathons, interviews, or practice purposes. The solutions provided here are very easy to follow and include detailed explanations.

Table of Contents

1. Problem Statement
2. Complexity Analysis
3. Count the Number of Vowel Strings in Range solution in C++
4. Count the Number of Vowel Strings in Range solution in Java
5. Count the Number of Vowel Strings in Range solution in Python
6. Additional Resources

Problem Statement of 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.

Constraints:

1 <= words.length <= 1000
1 <= words[i].length <= 10
words[i] consists of only lowercase English letters.
0 <= left <= right < words.length

Complexity Analysis

• Time Complexity: O(n)
• Space Complexity: O(1)

2586. Count the Number of Vowel Strings in Range LeetCode Solution in C++

class Solution {
 public:
  int vowelStrings(vector<string>& words, int left, int right) {
    return count_if(words.begin() + left, words.begin() + right + 1,
                    [this](const string& word) {
      return isVowel(word.front()) && isVowel(word.back());
    });
  }

 private:
  bool isVowel(char c) {
    static constexpr string_view kVowels = "aeiou";
    return kVowels.find(c) != string_view::npos;
  }
};
/* code provided by PROGIEZ */

2586. Count the Number of Vowel Strings in Range LeetCode Solution in Java

class Solution {
  public int vowelStrings(String[] words, int left, int right) {
    return (int) Arrays.asList(words)
        .subList(left, right + 1)
        .stream()
        .filter(word -> isVowel(word.charAt(0)) && isVowel(word.charAt(word.length() - 1)))
        .count();
  }

  private boolean isVowel(char c) {
    return "aeiou".indexOf(c) != -1;
  }
}
// code provided by PROGIEZ

2586. Count the Number of Vowel Strings in Range LeetCode Solution in Python

class Solution:
  def vowelStrings(self, words: list[str], left: int, right: int) -> int:
    kVowels = 'aeiou'
    return sum(word[0] in kVowels and word[-1] in kVowels
               for word in words[left:right + 1])
 # code by PROGIEZ

Additional Resources

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