Class Solution


  • public class Solution
    extends Object
    1641 - Count Sorted Vowel Strings.

    Medium

    Given an integer n, return the number of strings of length n that consist only of vowels (a, e, i, o, u) and are lexicographically sorted.

    A string s is lexicographically sorted if for all valid i, s[i] is the same as or comes before s[i+1] in the alphabet.

    Example 1:

    Input: n = 1

    Output: 5

    Explanation: The 5 sorted strings that consist of vowels only are ["a","e","i","o","u"].

    Example 2:

    Input: n = 2

    Output: 15

    Explanation: The 15 sorted strings that consist of vowels only are

    [“aa”,“ae”,“ai”,“ao”,“au”,“ee”,“ei”,“eo”,“eu”,“ii”,“io”,“iu”,“oo”,“ou”,“uu”].

    Note that “ea” is not a valid string since ‘e’ comes after ‘a’ in the alphabet.

    Example 3:

    Input: n = 33

    Output: 66045

    Constraints:

    • 1 <= n <= 50
    • Constructor Detail

      • Solution

        public Solution()
    • Method Detail

      • countVowelStrings

        public int countVowelStrings​(int n)