LeetCode-in-Java

2586. Count the Number of Vowel Strings in Range

Easy

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

Solution

public class Solution {
    public int vowelStrings(String[] words, int left, int right) {
        int count = 0;
        for (int i = left; i <= right; i++) {
            if (isVowel(words[i].charAt(0)) && isVowel(words[i].charAt(words[i].length() - 1))) {
                count++;
            }
        }
        return count;
    }

    private boolean isVowel(char ch) {
        String str = "aeiou";
        return str.indexOf(ch) != -1;
    }
}

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