Validate Matching Brackets

Validate Matching Brackets

In site reliability engineering, configuration validators and log processors often need to verify that structured expressions, such as queries, JSON snippets, or firewall rules, contain properly balanced brackets.

Write a function that takes a string s consisting solely of bracket characters ('(', ')', '{', '}', '[', ']') and returns True if the string is valid, and False otherwise.

A bracket sequence is considered valid if:

1. Open brackets are closed by the same type of brackets.
2. Open brackets are closed in the correct order.
3. Every close bracket has a corresponding open bracket of the same type.

Function Signature

def is_valid_brackets(s: str) -> bool:
    pass

Input and Output Format

• Input: A single string s of length n containing only '(', ')', '{', '}', '[', and ']'.
• Output: A boolean (True or False).

Constraints

• 0 <= len(s) <= 10^5
• The string contains only the six bracket characters: (, ), {, }, [, ].
• Time complexity should be O(n) and auxiliary space complexity should be O(n).

Examples

Example 1:

Input: s = "{[()]}"
Output: True
Explanation: Each opening bracket is closed by the corresponding closing bracket in reverse order of appearance.

Example 2:

Input: s = "([)]"
Output: False
Explanation: The square bracket is closed before the inner parenthesis is closed, violating nesting order.

Example 3:

Input: s = "]"
Output: False
Explanation: There is no preceding opening bracket for the closing square bracket.

Edge Cases to Consider

• Empty string: s = "" should return True.
• Odd-length string: Cannot be valid; can be short-circuited early.
• Unmatched opening brackets: For example, s = "(((".
• Unmatched closing brackets: For example, s = ")".