1220. Count Vowels Permutation

class Solution {
public:
    int countVowelPermutation(int n) {
        const int MOD = 1e9 + 7;
        vector<vector<long long>> dp(n, vector<long long>(5, 0));
        
        for (int i = 0; i < 5; ++i) {
            dp[0][i] = 1;
        }
        
        for (int i = 1; i < n; ++i) {
            dp[i][0] = (dp[i - 1][1] + dp[i - 1][2] + dp[i - 1][4]) % MOD;
            dp[i][1] = (dp[i - 1][0] + dp[i - 1][2]) % MOD;
            dp[i][2] = (dp[i - 1][1] + dp[i - 1][3]) % MOD;
            dp[i][3] = dp[i - 1][2];
            dp[i][4] = (dp[i - 1][2] + dp[i - 1][3]) % MOD;
        }
        
        long long total = 0;
        for (int i = 0; i < 5; ++i) {
            total = (total + dp[n - 1][i]) % MOD;
        }
        
        return total;
    }
};