<h2 id="heading-url">URL</h2>
<a target="_blank" href="https://leetcode.com/problems/destination-city/description/?envType=daily-question&amp;envId=2023-12-15">https://leetcode.com/problems/destination-city/description/?envType=daily-question&amp;envId=2023-12-15</a>
<h2 id="heading-code">Code</h2>
<a target="_blank" href="https://github.com/syohex/dotnet-study/blob/master/fsharp/leetcode/problems/1436/main.fsx">https://github.com/syohex/dotnet-study/blob/master/fsharp/leetcode/problems/1436/main.fsx</a>
<pre><code class="lang-fsharp">let destCity (paths: (string * string) list) : string =
 let rec destCity' cities froms =
 match cities with
 | [] -&gt; failwith "never reach here"
 | city :: t -&gt; if Set.contains city froms then destCity' t froms else city

 let cities = paths |&gt; List.fold (fun acc (a, b) -&gt; b :: a :: acc) []

 let froms = paths |&gt; List.map fst |&gt; Set.ofList
 destCity' cities froms
</code></pre>

## URL

[https://leetcode.com/problems/destination-city/description/?envType=daily-question&envId=2023-12-15](https://leetcode.com/problems/destination-city/description/?envType=daily-question&envId=2023-12-15)

## Code

[https://github.com/syohex/dotnet-study/blob/master/fsharp/leetcode/problems/1436/main.fsx](https://github.com/syohex/dotnet-study/blob/master/fsharp/leetcode/problems/1436/main.fsx)

```fsharp
let destCity (paths: (string * string) list) : string =
    let rec destCity' cities froms =
        match cities with
        | [] -> failwith "never reach here"
        | city :: t -> if Set.contains city froms then destCity' t froms else city

    let cities = paths |> List.fold (fun acc (a, b) -> b :: a :: acc) []

    let froms = paths |> List.map fst |> Set.ofList
    destCity' cities froms
```

LeetCode 1436. Destination City in F#

URL

Code