- Difficulty: Medium
- Tags: LeetCode, Medium, String, Sliding Window, leetcode-1839, O(n), O(1)
Problem
A string is considered beautiful if it satisfies the following conditions:
- Each of the 5 English vowels (
'a'
,'e'
,'i'
,'o'
,'u'
) must appear at least once in it. - The letters must be sorted in alphabetical order (i.e. all
'a'
s before'e'
s, all'e'
s before'i'
s, etc.).
For example, strings "aeiou"
and "aaaaaaeiiiioou"
are considered beautiful, but "uaeio"
, "aeoiu"
, and "aaaeeeooo"
are not beautiful.
Given a string word
consisting of English vowels, return the length of the longest beautiful substring of word
. If no such substring exists, return 0
.
A substring is a contiguous sequence of characters in a string.
Example 1:
Input: word = "aeiaaioaaaaeiiiiouuuooaauuaeiu" Output: 13 Explanation: The longest beautiful substring in word is "aaaaeiiiiouuu" of length 13.
Example 2:
Input: word = "aeeeiiiioooauuuaeiou" Output: 5 Explanation: The longest beautiful substring in word is "aeiou" of length 5.
Example 3:
Input: word = "a" Output: 0 Explanation: There is no beautiful substring, so return 0.
Constraints:
1 <= word.length <= 5 * 105
word
consists of characters'a'
,'e'
,'i'
,'o'
, and'u'
.