leetcode2062: Count Vowel Substrings of a String

### Description

A substring is a contiguous (non-empty) sequence of characters within a string.

A vowel substring is a substring that only consists of vowels ('a', 'e', 'i', 'o', and 'u') and has all five vowels present in it.

Given a string word, return the number of vowel substrings in word.

Example 1:

Input: word = "aeiouu"
Output: 2
Explanation: The vowel substrings of word are as follows (underlined):
- "**aeiou**u"
- "**aeiouu**"

Example 2:

Input: word = "unicornarihan"
Output: 0
Explanation: Not all 5 vowels are present, so there are no vowel substrings.

Example 3:

Input: word = "cuaieuouac"
Output: 7
Explanation: The vowel substrings of word are as follows (underlined):
- "c**uaieu**ouac"
- "c**uaieuo**uac"
- "c**uaieuou**ac"
- "c**uaieuoua**c"
- "cu**aieuo**uac"
- "cu**aieuou**ac"
- "cu**aieuoua**c"

Constraints:

1 <= word.length <= 100
word consists of lowercase English letters only.