<h2 id="heading-url">URL</h2>
<p><a href="https://leetcode.com/problems/binary-trees-with-factors/" class="autolinkedURL autolinkedURL-url" target="_blank">leetcode.com/problems/binary-trees-with-fac..</a></p>
<h2 id="heading-code">Code</h2>
<p><a href="https://github.com/syohex/dotnet-study/blob/master/fsharp/leetcode/problems/0823/main.fsx" class="autolinkedURL autolinkedURL-url" target="_blank">github.com/syohex/dotnet-study/blob/master/..</a></p>
<pre><code class="lang-fsharp">let numFactoredBinaryTrees (arr: int []) : int =
    let arr' = arr |&gt; Array.sort

    let h =
        arr'
        |&gt; Array.mapi (fun i n -&gt; i, n)
        |&gt; Array.fold (fun acc (i, n) -&gt; Map.add n i acc) Map.empty

    let dp = Array.init arr'.Length (fun _ -&gt; 1L)
    let MOD = 1_000_000_007L

    for i in 1 .. (arr'.Length - 1) do
        for j in 0 .. (i - 1) do
            if arr'.[i] % arr'.[j] = 0 then
                match Map.tryFind (arr'.[i] / arr'.[j]) h with
                | Some (v) -&gt; dp.[i] &lt;- (dp.[i] + (dp.[j] * dp.[v])) % MOD
                | None -&gt; ()

    dp
    |&gt; Array.fold (fun acc n -&gt; (acc + n) % MOD) 0L
    |&gt; int
</code></pre>


## URL

https://leetcode.com/problems/binary-trees-with-factors/

## Code

https://github.com/syohex/dotnet-study/blob/master/fsharp/leetcode/problems/0823/main.fsx

```fsharp
let numFactoredBinaryTrees (arr: int []) : int =
    let arr' = arr |> Array.sort

    let h =
        arr'
        |> Array.mapi (fun i n -> i, n)
        |> Array.fold (fun acc (i, n) -> Map.add n i acc) Map.empty

    let dp = Array.init arr'.Length (fun _ -> 1L)
    let MOD = 1_000_000_007L

    for i in 1 .. (arr'.Length - 1) do
        for j in 0 .. (i - 1) do
            if arr'.[i] % arr'.[j] = 0 then
                match Map.tryFind (arr'.[i] / arr'.[j]) h with
                | Some (v) -> dp.[i] <- (dp.[i] + (dp.[j] * dp.[v])) % MOD
                | None -> ()

    dp
    |> Array.fold (fun acc n -> (acc + n) % MOD) 0L
    |> int
```

LeetCode 823. Binary Trees With Factors in F#

URL

Code