<h2 id="heading-url">URL</h2>
<p><a href="https://leetcode.com/problems/n-queens-ii/" class="autolinkedURL autolinkedURL-url" target="_blank">leetcode.com/problems/n-queens-ii</a></p>
<h2 id="heading-code">Code</h2>
<p><a href="https://github.com/syohex/dotnet-study/blob/master/fsharp/leetcode/problems/0052/main.fsx" class="autolinkedURL autolinkedURL-url" target="_blank">github.com/syohex/dotnet-study/blob/master/..</a></p>
<pre><code class="lang-fsharp">open System

let totalNQueens (n: int) : int =
    let rec totalNQueens' p n acc =
        if p = n then
            1
        else
            seq { 0 .. (n - 1) }
            |&gt; Seq.fold
                (fun ret m -&gt;
                    let ok =
                        acc
                        |&gt; List.mapi (fun i j -&gt; i + 1, j)
                        |&gt; List.forall (fun (i, j) -&gt; j &lt;&gt; m &amp;&amp; Math.Abs(j - m) &lt;&gt; i)

                    if ok then
                        ret + totalNQueens' (p + 1) n (m :: acc)
                    else
                        ret)
                0

    totalNQueens' 0 n []
</code></pre>


## URL

https://leetcode.com/problems/n-queens-ii/

## Code

https://github.com/syohex/dotnet-study/blob/master/fsharp/leetcode/problems/0052/main.fsx

```fsharp
open System

let totalNQueens (n: int) : int =
    let rec totalNQueens' p n acc =
        if p = n then
            1
        else
            seq { 0 .. (n - 1) }
            |> Seq.fold
                (fun ret m ->
                    let ok =
                        acc
                        |> List.mapi (fun i j -> i + 1, j)
                        |> List.forall (fun (i, j) -> j <> m && Math.Abs(j - m) <> i)

                    if ok then
                        ret + totalNQueens' (p + 1) n (m :: acc)
                    else
                        ret)
                0

    totalNQueens' 0 n []
```

LeetCode 52. N-Queens II in F#

URL

Code