<h2 id="heading-url">URL</h2>
<p><a target="_blank" href="https://leetcode.com/problems/matrix-diagonal-sum/description/">Matrix Diagonal Sum - LeetCode</a></p>
<h2 id="heading-code">Code</h2>
<p><a target="_blank" href="https://github.com/syohex/dotnet-study/tree/master/fsharp/leetcode/problems/1572/main.fsx">https://github.com/syohex/dotnet-study/tree/master/fsharp/leetcode/problems/1572/main.fsx</a></p>
<pre><code class="lang-plaintext">let diagonalSum (mat: int[,]) : int =
    let rec diagonalSum' i n (mat: int[,]) acc =
        if i = n then
            if n % 2 = 0 then
                acc
            else
                let half = n / 2
                acc - mat.[half, half]
        else
            let acc' = acc + mat.[i, i] + mat.[n - 1 - i, i]
            diagonalSum' (i + 1) n mat acc'

    diagonalSum' 0 (Array2D.length1 mat) mat 0
</code></pre>


## URL

[Matrix Diagonal Sum - LeetCode](https://leetcode.com/problems/matrix-diagonal-sum/description/)

## Code

[https://github.com/syohex/dotnet-study/tree/master/fsharp/leetcode/problems/1572/main.fsx](https://github.com/syohex/dotnet-study/tree/master/fsharp/leetcode/problems/1572/main.fsx)

```plaintext
let diagonalSum (mat: int[,]) : int =
    let rec diagonalSum' i n (mat: int[,]) acc =
        if i = n then
            if n % 2 = 0 then
                acc
            else
                let half = n / 2
                acc - mat.[half, half]
        else
            let acc' = acc + mat.[i, i] + mat.[n - 1 - i, i]
            diagonalSum' (i + 1) n mat acc'

    diagonalSum' 0 (Array2D.length1 mat) mat 0
```

LeetCode 1572. Matrix Diagonal Sum in F#

URL

Code