<h2 id="heading-url">URL</h2>
<a target="_blank" href="https://leetcode.com/problems/parsing-a-boolean-expression/description/?envType=daily-question&amp;envId=2024-10-20">https://leetcode.com/problems/parsing-a-boolean-expression/description/?envType=daily-question&amp;envId=2024-10-20</a>
<h2 id="heading-code">Code</h2>
<a target="_blank" href="https://github.com/syohex/dotnet-study/tree/master/fsharp/leetcode/challenge/202410/parsing_a_boolean_expression/main.fsx">https://github.com/syohex/dotnet-study/tree/master/fsharp/leetcode/challenge/202410/parsing_a_boolean_expression/main.fsx</a>
<pre><code class="lang-fsharp">let parseBoolExpr (expression: string) : bool =
 let rec parseBoolExpr' cs =
 match cs with
 | [] -&gt; true, []
 | 't' :: t -&gt; true, t
 | 'f' :: t -&gt; false, t
 | '!' :: '(' :: t -&gt;
 let v, cs = parseBoolExpr' t
 not v, List.tail cs
 | '&amp;' :: '(' :: t -&gt;
 let exprs, t = parseExprs t []
 List.reduce (&amp;&amp;) exprs, t
 | '|' :: '(' :: t -&gt;
 let exprs, t = parseExprs t []
 List.reduce (||) exprs, t
 | _ -&gt; failwith "never reach here"

 and parseExprs cs acc =
 match cs with
 | [] -&gt; failwith ") is not found"
 | ')' :: t -&gt; acc, t
 | ',' :: t -&gt; parseExprs t acc
 | _ -&gt;
 let v, t = parseBoolExpr' cs
 parseExprs t (v :: acc)

 parseBoolExpr' (Seq.toList expression) |&gt; fst
</code></pre>

## URL

[https://leetcode.com/problems/parsing-a-boolean-expression/description/?envType=daily-question&envId=2024-10-20](https://leetcode.com/problems/parsing-a-boolean-expression/description/?envType=daily-question&envId=2024-10-20)

## Code

[https://github.com/syohex/dotnet-study/tree/master/fsharp/leetcode/challenge/202410/parsing\_a\_boolean\_expression/main.fsx](https://github.com/syohex/dotnet-study/tree/master/fsharp/leetcode/challenge/202410/parsing_a_boolean_expression/main.fsx)

```fsharp
let parseBoolExpr (expression: string) : bool =
    let rec parseBoolExpr' cs =
        match cs with
        | [] -> true, []
        | 't' :: t -> true, t
        | 'f' :: t -> false, t
        | '!' :: '(' :: t ->
            let v, cs = parseBoolExpr' t
            not v, List.tail cs
        | '&' :: '(' :: t ->
            let exprs, t = parseExprs t []
            List.reduce (&&) exprs, t
        | '|' :: '(' :: t ->
            let exprs, t = parseExprs t []
            List.reduce (||) exprs, t
        | _ -> failwith "never reach here"

    and parseExprs cs acc =
        match cs with
        | [] -> failwith ") is not found"
        | ')' :: t -> acc, t
        | ',' :: t -> parseExprs t acc
        | _ ->
            let v, t = parseBoolExpr' cs
            parseExprs t (v :: acc)

    parseBoolExpr' (Seq.toList expression) |> fst
```

LeetCode 1106. Parsing A Boolean Expression in F#

URL

Code