Solution: Count Vowel Substrings of a String

Statement

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

A substring of word is considered a vowel substring if both of the following are true:

1. Every character in the substring is a vowel from the set {a, e, i, o, u}.

2. The substring contains each of the five vowels a, e, i, o, and u at least once.

Constraints:

• $1 \leq$ ...