力扣讨论区 字符串 一道题目

看到一道题目 不知道这种题目的最优解法应该是怎么样的?
Consider a string, s = "abc". An alphabetically-ordered sequence of substrings of s would be {"a", "ab", "abc", "b", "bc", "c"}. If we reduce this sequence to only those substrings that start with a vowel and end with a consonant, we're left with {"ab", "abc"}. The alphabetically first element in this reduced list is "ab", and the alphabetically last element is "abc". As a reminder:
Vowels: a, e, i, o, and u.
Consonants: b, c, d, f, g, h, j, k, l, m, n, p, q, r, s, t, v, w, x, y, and z.
Complete the findSubstrings function in your editor. It has 1 parameter: a string, s, consisting of lowercase English letters (a − z). The function must find the substrings of s that start with a vowel and end with a consonant, then print the alphabetically first and alphabetically last of these substrings.
Input Format
The locked stub code in your editor reads a single string, s, from stdin and passes it to your function.
Constraints
3 ≤ length of s ≤ 5 × 10^5