1963. Minimum Number of Swaps to Make the String Balanced

You are given a 0-indexed string s of even length n. The string consists of exactly n / 2 opening brackets '[' and n / 2 closing brackets ']'. A string is called balanced if and only if: - It is the empty string, or - It can be written as AB, where both A and B are balanced strings, or - It can be written as [C], where C is a balanced string. You may swap the brackets at any two indices any n