prefix of size n+1 where n is the length of words, with all elements set to 0.words array, and for each word, check if it starts and ends with a vowel.prefix array.prefix array to contain the cumulative sum up to the current index.ans to store the results of the queries.queries array, and for each query [li, ri], calculate the number of words starting and ending with a vowel in the range by subtracting prefix[li] from prefix[ri + 1].ans list.ans list.