Longest Balanced Parentheses Substring

### Problem You receive a string `brackets` whose characters are all `(` or `)`. Return the greatest length of a contiguous substring that forms a well-formed parentheses sequence. A well-formed sequence pairs every opening parenthesis with a closing parenthesis in the correct nesting order. The characters you select must be adjacent in the original string; you cannot remove characters from the middle of a substring. Return `0` if the string contains no nonempty well-formed substring, including when `brackets` is empty. ### Examples **Example 1** ```text Input: brackets = ")((()))()(" Output: 8 ``` The substring `((()))()` is well formed and contains eight characters. Neither character just outside it can extend it into a longer well-formed substring. **Example 2** ```text Input: brackets = "(((" Output: 0 ``` There are no closing parentheses, so no nonempty substring is well formed. ### Constraints - `0 <= brackets.length <= 3 * 10^4` - Every character of `brackets` is `(` or `)`.