<h2 id="heading-url">URL</h2>
<a target="_blank" href="https://leetcode.com/problems/binary-trees-with-factors/description/?envType=daily-question&amp;envId=2023-10-26">Binary Trees With Factors - LeetCode</a>
<h2 id="heading-code">Code</h2>
<a target="_blank" href="https://github.com/syohex/dotnet-study/tree/master/fsharp/leetcode/challenge/202310/binary_trees_with_factors/main.fsx">https://github.com/syohex/dotnet-study/tree/master/fsharp/leetcode/challenge/202310/binary_trees_with_factors/main.fsx</a>
<pre><code class="lang-fsharp">let numFactoredBinaryTrees (arr: int[]) : int =
 let modulo = 1_000_000_007L

 let arr = Array.sort arr

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

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

 for i in 0 .. (len - 1) do
 for j in 0 .. (i - 1) do
 if arr.[i] % arr.[j] = 0 then
 match Map.tryFind (arr.[i] / arr.[j]) valueIndex with
 | Some(other) -&gt; dp.[i] &lt;- (dp.[i] + (dp.[j] * dp.[other])) % modulo
 | None -&gt; ()

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

## URL

[Binary Trees With Factors - LeetCode](https://leetcode.com/problems/binary-trees-with-factors/description/?envType=daily-question&envId=2023-10-26)

## Code

[https://github.com/syohex/dotnet-study/tree/master/fsharp/leetcode/challenge/202310/binary\_trees\_with\_factors/main.fsx](https://github.com/syohex/dotnet-study/tree/master/fsharp/leetcode/challenge/202310/binary_trees_with_factors/main.fsx)

```fsharp
let numFactoredBinaryTrees (arr: int[]) : int =
 let modulo = 1_000_000_007L

 let arr = Array.sort arr

 let valueIndex =
 arr |> Array.indexed |> Array.fold (fun acc (i, n) -> Map.add n i acc) Map.empty

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

 for i in 0 .. (len - 1) do
 for j in 0 .. (i - 1) do
 if arr.[i] % arr.[j] = 0 then
 match Map.tryFind (arr.[i] / arr.[j]) valueIndex with
 | Some(other) -> dp.[i] <- (dp.[i] + (dp.[j] * dp.[other])) % modulo
 | None -> ()

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

LeetCode 823. Binary Trees With Factors in F#

URL

Code