<h2 id="heading-url">URL</h2>
<p><a target="_blank" href="https://leetcode.com/problems/binary-tree-preorder-traversal/description/">https://leetcode.com/problems/binary-tree-preorder-traversal/description/</a></p>
<h2 id="heading-code">Code</h2>
<p><a target="_blank" href="https://github.com/syohex/dotnet-study/blob/master/fsharp/leetcode/problems/0144/main.fsx">https://github.com/syohex/dotnet-study/blob/master/fsharp/leetcode/problems/0144/main.fsx</a></p>
<pre><code class="lang-plaintext">type Tree =
    | Leaf
    | Node of int * Tree * Tree

let preorderTraversal (root: Tree) : int list =
    let rec preorderTraversal' node acc =
        match node with
        | Leaf -&gt; acc
        | Node (v, left, right) -&gt;
            (v :: acc)
            |&gt; preorderTraversal' left
            |&gt; preorderTraversal' right

    preorderTraversal' root [] |&gt; List.rev
</code></pre>


## URL

[https://leetcode.com/problems/binary-tree-preorder-traversal/description/](https://leetcode.com/problems/binary-tree-preorder-traversal/description/)

## Code

[https://github.com/syohex/dotnet-study/blob/master/fsharp/leetcode/problems/0144/main.fsx](https://github.com/syohex/dotnet-study/blob/master/fsharp/leetcode/problems/0144/main.fsx)

```plaintext
type Tree =
    | Leaf
    | Node of int * Tree * Tree

let preorderTraversal (root: Tree) : int list =
    let rec preorderTraversal' node acc =
        match node with
        | Leaf -> acc
        | Node (v, left, right) ->
            (v :: acc)
            |> preorderTraversal' left
            |> preorderTraversal' right

    preorderTraversal' root [] |> List.rev
```

LeetCode 144. Binary Tree Preorder Traversal in F#

URL

Code