<h2 id="heading-url">URL</h2>
<a target="_blank" href="https://leetcode.com/problems/find-largest-value-in-each-tree-row/description/?envType=daily-question&amp;envId=2023-10-24">Find Largest Value in Each Tree Row - LeetCode</a>
<h2 id="heading-code">Code</h2>
<a target="_blank" href="https://github.com/syohex/dotnet-study/tree/master/fsharp/leetcode/problems/0515/main.fsx">https://github.com/syohex/dotnet-study/tree/master/fsharp/leetcode/problems/0515/main.fsx</a>
<pre><code class="lang-fsharp">open System

type TreeNode =
 | Leaf
 | Node of int * TreeNode * TreeNode

let largestValues (root: TreeNode) : int list =
 let rec largestValues' q acc =
 match q with
 | [] -&gt; List.rev acc
 | _ -&gt;
 let q', max =
 q
 |&gt; List.fold
 (fun (q, max) node -&gt;
 match node with
 | Leaf -&gt; failwith "never reach here"
 | Node(v, left, right) -&gt;
 let max' = Math.Max(max, v)

 match left, right with
 | Leaf, Leaf -&gt; q, max'
 | Leaf, Node(_) -&gt; right :: q, max'
 | Node(_), Leaf -&gt; left :: q, max'
 | _, _ -&gt; left :: right :: q, max')
 ([], Int32.MinValue)

 largestValues' q' (max :: acc)

 match root with
 | Leaf -&gt; []
 | _ -&gt; largestValues' [ root ] []
</code></pre>

## URL

[Find Largest Value in Each Tree Row - LeetCode](https://leetcode.com/problems/find-largest-value-in-each-tree-row/description/?envType=daily-question&envId=2023-10-24)

## Code

[https://github.com/syohex/dotnet-study/tree/master/fsharp/leetcode/problems/0515/main.fsx](https://github.com/syohex/dotnet-study/tree/master/fsharp/leetcode/problems/0515/main.fsx)

```fsharp
open System

type TreeNode =
    | Leaf
    | Node of int * TreeNode * TreeNode

let largestValues (root: TreeNode) : int list =
    let rec largestValues' q acc =
        match q with
        | [] -> List.rev acc
        | _ ->
            let q', max =
                q
                |> List.fold
                    (fun (q, max) node ->
                        match node with
                        | Leaf -> failwith "never reach here"
                        | Node(v, left, right) ->
                            let max' = Math.Max(max, v)

                            match left, right with
                            | Leaf, Leaf -> q, max'
                            | Leaf, Node(_) -> right :: q, max'
                            | Node(_), Leaf -> left :: q, max'
                            | _, _ -> left :: right :: q, max')
                    ([], Int32.MinValue)

            largestValues' q' (max :: acc)

    match root with
    | Leaf -> []
    | _ -> largestValues' [ root ] []
```

LeetCode 515. Find Largest Value in Each Tree Row in F#

URL

Code