2023.10.30 Today's Challenge

fabichoi 2023. 10. 30. 23:45

https://leetcode.com/problems/count-vowels-permutation/?envType=daily-question&envId=2023-10-28

Count Vowels Permutation - LeetCode

Can you solve this real interview question? Count Vowels Permutation - Given an integer n, your task is to count how many strings of length n can be formed under the following rules: * Each character is a lower case vowel ('a', 'e', 'i', 'o', 'u') * Each

leetcode.com

이것도 왜 hard지..?

class Solution:
    def countVowelPermutation(self, n: int) -> int:
        MOD = 10**9 + 7
        a, e, i, o, u = 1, 1, 1, 1, 1

        for _ in range(1, n):
            a_next = e
            e_next = (a + i) % MOD
            i_next = (a + e + o + u) % MOD
            o_next = (i + u) % MOD
            u_next = a

            a, e, i, o, u = a_next, e_next, i_next, o_next, u_next
        
        return (a + e + i + o + u) % MOD