<h2 id="heading-url">URL</h2>
<p><a href="https://leetcode.com/problems/count-vowels-permutation/" class="autolinkedURL autolinkedURL-url" target="_blank">leetcode.com/problems/count-vowels-permutat..</a></p>
<h2 id="heading-code">Code</h2>
<p><a href="https://github.com/syohex/dotnet-study/blob/master/fsharp/leetcode/problems/1220/main.fsx" class="autolinkedURL autolinkedURL-url" target="_blank">github.com/syohex/dotnet-study/blob/master/..</a></p>
<pre><code class="lang-fsharp">let countVowelPermutation (n: int) : int =
    let dp = Array2D.init 5 n (fun _ _ -&gt; 0L)

    for i in 0..4 do
        dp.[i, 0] &lt;- 1L

    let MOD = 1_000_000_007L

    for i in 1 .. (n - 1) do
        dp.[0, i] &lt;- dp.[1, i - 1]
        dp.[1, i] &lt;- (dp.[0, i - 1] + dp.[2, i - 1]) % MOD

        dp.[2, i] &lt;-
            (dp.[0, i - 1]
             + dp.[1, i - 1]
             + dp.[3, i - 1]
             + dp[4, i - 1]) % MOD

        dp.[3, i] &lt;- (dp.[2, i - 1] + dp.[4, i - 1]) % MOD
        dp.[4, i] &lt;- dp.[0, i - 1]

    seq { 0..4 }
    |&gt; Seq.fold (fun acc i -&gt; (acc + dp.[i, n - 1]) % MOD) 0L
    |&gt; int
</code></pre>


## URL

https://leetcode.com/problems/count-vowels-permutation/

## Code

https://github.com/syohex/dotnet-study/blob/master/fsharp/leetcode/problems/1220/main.fsx

```fsharp
let countVowelPermutation (n: int) : int =
    let dp = Array2D.init 5 n (fun _ _ -> 0L)

    for i in 0..4 do
        dp.[i, 0] <- 1L

    let MOD = 1_000_000_007L

    for i in 1 .. (n - 1) do
        dp.[0, i] <- dp.[1, i - 1]
        dp.[1, i] <- (dp.[0, i - 1] + dp.[2, i - 1]) % MOD

        dp.[2, i] <-
            (dp.[0, i - 1]
             + dp.[1, i - 1]
             + dp.[3, i - 1]
             + dp[4, i - 1]) % MOD

        dp.[3, i] <- (dp.[2, i - 1] + dp.[4, i - 1]) % MOD
        dp.[4, i] <- dp.[0, i - 1]

    seq { 0..4 }
    |> Seq.fold (fun acc i -> (acc + dp.[i, n - 1]) % MOD) 0L
    |> int
```

LeetCode 1220. Count Vowels Permutation in F#

URL

Code