1220-count-vowels-permutation.py

class Solution:
    def countVowelPermutation(self, n: int) -> int:

        a_vowel_permutation_count = [1] * n
        e_vowel_permutation_count = [1] * n
        i_vowel_permutation_count = [1] * n
        o_vowel_permutation_count = [1] * n
        u_vowel_permutation_count = [1] * n

        MOD = 10 ** 9 + 7

        for i in range(1, n):
            a_vowel_permutation_count[i] = (
                e_vowel_permutation_count[i - 1] + i_vowel_permutation_count[i - 1] + u_vowel_permutation_count[i - 1]) % MOD
            e_vowel_permutation_count[i] = (
                a_vowel_permutation_count[i - 1] + i_vowel_permutation_count[i - 1]) % MOD
            i_vowel_permutation_count[i] = (
                e_vowel_permutation_count[i - 1] + o_vowel_permutation_count[i - 1]) % MOD
            o_vowel_permutation_count[i] = (
                i_vowel_permutation_count[i - 1]) % MOD
            u_vowel_permutation_count[i] = (
                i_vowel_permutation_count[i - 1] + o_vowel_permutation_count[i - 1]) % MOD

        result = 0

        result = (a_vowel_permutation_count[n - 1] + e_vowel_permutation_count[n - 1] +
                  i_vowel_permutation_count[n - 1] + o_vowel_permutation_count[n - 1] +
                  u_vowel_permutation_count[n - 1]) % MOD

        return result