hardDynamic Programming 0 views
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: Since the answer may be too large, return it modulo 10^9 + 7.
Given an integer n, your task is to count how many strings of length n can be formed under the following rules:
Since the answer may be too large, return it modulo 10^9 + 7.
Example 1
Input: n = 1
Output: 5
Explanation: All possible strings are: "a", "e", "i" , "o" and "u".
Example 2
Input: n = 2
Output: 10
Explanation: All possible strings are: "ae", "ea", "ei", "ia", "ie", "io", "iu", "oi", "ou" and "ua".
Example 3
Input: n = 5
Output: 68
Constraints
- 1 <= n <= 2 * 10^4
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