LeetCode 3713. Longest Balanced Substring I in F#

URL https://leetcode.com/problems/longest-balanced-substring-i/description/?envType=daily-question&envId=2026-02-12 Code https://github.com/syohex/dotnet-study/blob/main/fsharp/leetcode/challenge/202602/longest_balanced_substring1/main.fsx let longes...