Minimum Number of Swaps to Make the String

lcpy gen -n 1963   # by problem number
lcpy gen -s minimum_number_of_swaps_to_make_the_string_balanced   # by problem name

Input: s = "][]["
Output: 1
Explanation: You can make the string balanced by swapping index 0 with index 3.
The resulting string is "[[]]".

Input: s = "]]][[["
Output: 2
Explanation: You can do the following to make the string balanced:
- Swap index 0 with index 4. s = "[]][][".
- Swap index 1 with index 5. s = "[[][]]".
The resulting string is "[[][]]".

Input: s = "[]"
Output: 0
Explanation: The string is already balanced.

class Solution:
    # Time: O(n)
    # Space: O(1)
    def min_swaps(self, s: str) -> int:
        unmatched_close = 0
        max_unmatched_close = 0
        for ch in s:
            if ch == "]":
                unmatched_close += 1
                max_unmatched_close = max(max_unmatched_close, unmatched_close)
            else:
                unmatched_close -= 1
        return (max_unmatched_close + 1) // 2