Stack-based solution, pretty much what you'd expect.
Start by clarifying the problem: which bracket types are included, and whether the string may contain other characters. Then propose a stack-based solution that pushes opening brackets and pops when a matching closing bracket is encountered, returning false if a mismatch or leftover opening brackets exist.
Pro tip: Mention edge cases like empty string, single bracket, and strings with non-bracket characters, and discuss the time and space complexity (O(n) time, O(n) space) to show thoroughness. Also, briefly note that a counter-based approach works only for a single bracket type, but a stack is needed for multiple types.
Ask the interviewer which bracket types to consider (e.g., (), [], {}) and whether the string can contain other characters. Confirm that an empty string is considered valid.
Explain that a stack is ideal because brackets must be closed in LIFO order. Mention that a simple counter works only for one bracket type, but a stack handles multiple types.
Iterate through each character: if it's an opening bracket, push it; if it's a closing bracket, check if the stack is empty or the top doesn't match, then return false; otherwise pop. After the loop, return true only if the stack is empty.
State that the time complexity is O(n) because each character is processed once, and space complexity is O(n) in the worst case (e.g., all opening brackets).
Walk through examples like '()[]{}', '([)]', and '{[]}' to demonstrate correctness and edge cases. Mention that non-bracket characters can be ignored or handled based on clarification.
AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.