<h2 id="heading-url">URL</h2>
<p><a target="_blank" href="https://leetcode.com/problems/find-smallest-letter-greater-than-target/description/">Find Smallest Letter Greater Than Target - 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/0744/main.fsx">https://github.com/syohex/dotnet-study/tree/master/fsharp/leetcode/problems/0744/main.fsx</a></p>
<pre><code class="lang-plaintext">let nextGreatestLetter (letters: char[]) (target: char) : char =
    let rec nextGreatestLetter' left right (letters: char[]) =
        if left &gt; right then
            if left &gt;= letters.Length then
                letters.[0]
            else
                letters.[left]
        else
            let mid = left + (right - left) / 2

            if letters.[mid] &gt; target then
                nextGreatestLetter' left (mid - 1) letters
            else
                nextGreatestLetter' (mid + 1) right letters

    nextGreatestLetter' 0 (letters.Length - 1) letters
</code></pre>


## URL

[Find Smallest Letter Greater Than Target - LeetCode](https://leetcode.com/problems/find-smallest-letter-greater-than-target/description/)

## Code

[https://github.com/syohex/dotnet-study/tree/master/fsharp/leetcode/problems/0744/main.fsx](https://github.com/syohex/dotnet-study/tree/master/fsharp/leetcode/problems/0744/main.fsx)

```plaintext
let nextGreatestLetter (letters: char[]) (target: char) : char =
    let rec nextGreatestLetter' left right (letters: char[]) =
        if left > right then
            if left >= letters.Length then
                letters.[0]
            else
                letters.[left]
        else
            let mid = left + (right - left) / 2

            if letters.[mid] > target then
                nextGreatestLetter' left (mid - 1) letters
            else
                nextGreatestLetter' (mid + 1) right letters

    nextGreatestLetter' 0 (letters.Length - 1) letters
```

LeetCode 744. Find Smallest Letter Greater Than Target in F#

URL

Code