Clarify the problem constraints (e.g., only bracket characters, types of brackets) and then propose a stack-based solution. Walk through the algorithm step-by-step, analyze time and space complexity, and discuss edge cases and potential optimizations.
Pro tip: Mention that a stack is ideal because brackets follow a last-in-first-out (LIFO) order, and proactively discuss how to handle multiple bracket types and early termination for efficiency.
Ask about the types of brackets (e.g., (), [], {}), whether the string can be empty, and if there are any constraints on length or character set. Confirm that the function should return a boolean.
Explain that you'll iterate through the string, pushing opening brackets onto a stack and popping when encountering a closing bracket, checking for matches. If the stack is empty at the end, brackets are balanced.
Trace the algorithm on a sample input like '{[()]}' to demonstrate correctness, and also on an invalid input like '([)]' to show how mismatches are detected.
State that time complexity is O(n) and space complexity is O(n) in the worst case. Discuss edge cases: empty string, single bracket, nested brackets, and early termination when a mismatch is found.
Mention that for a single bracket type, a counter could suffice, but a stack is necessary for multiple types. Also note that early return on mismatch improves average-case performance.
AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.