<h2 id="heading-url">URL</h2>
<p><a href="https://leetcode.com/problems/construct-string-from-binary-tree/" class="autolinkedURL autolinkedURL-url" target="_blank">leetcode.com/problems/construct-string-from..</a></p>
<h2 id="heading-code">Code</h2>
<p><a href="https://github.com/syohex/dotnet-study/blob/master/fsharp/leetcode/problems/0606/main.fsx" class="autolinkedURL autolinkedURL-url" target="_blank">github.com/syohex/dotnet-study/blob/master/..</a></p>
<pre><code class="lang-fsharp">type Tree =
    | Leaf
    | Node of int * Tree * Tree

let tree2str (root: Tree) : string =
    let rec tree2str' node : string =
        match node with
        | Leaf -&gt; ""
        | Node (v, left, right) -&gt;
            let mutable ret = string v
            let tmp1 = tree2str' left
            let tmp2 = tree2str' right

            if tmp1.Length &lt;&gt; 0 then
                ret &lt;- ret + "(" + tmp1 + ")"

            if tmp2.Length &lt;&gt; 0 then
                if tmp1.Length = 0 then
                    ret &lt;- ret + "()"

                ret &lt;- ret + "(" + tmp2 + ")"

            ret

    tree2str' root
</code></pre>


## URL

https://leetcode.com/problems/construct-string-from-binary-tree/

## Code

https://github.com/syohex/dotnet-study/blob/master/fsharp/leetcode/problems/0606/main.fsx

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

let tree2str (root: Tree) : string =
    let rec tree2str' node : string =
        match node with
        | Leaf -> ""
        | Node (v, left, right) ->
            let mutable ret = string v
            let tmp1 = tree2str' left
            let tmp2 = tree2str' right

            if tmp1.Length <> 0 then
                ret <- ret + "(" + tmp1 + ")"

            if tmp2.Length <> 0 then
                if tmp1.Length = 0 then
                    ret <- ret + "()"

                ret <- ret + "(" + tmp2 + ")"

            ret

    tree2str' root
```

LeetCode 606. Construct String from Binary Tree in F#

URL

Code