I started with the linear scan plus a frequency map approach, which they seemed fine with.
Start by clarifying the requirements and edge cases, then design a modular validation system where each rule is a separate function that returns a result. Implement the validator to run all rules and collect failures, ensuring extensibility and testability.
Pro tip: Emphasize that returning all failed rules (not just the first) improves user experience and debugging, and mention that rules should be pure functions to simplify testing and future additions.
Ask about the exact rule set, whether rules are mandatory or optional, and how to handle edge cases like empty passwords or null inputs. Confirm the expected output format (e.g., boolean and list of failed rules).
Propose representing each rule as a separate function or object with a common interface (e.g., validate(password) -> bool). This allows easy addition, removal, or reordering of rules without modifying core logic.
Write a validator that iterates over the configured rules, applies each to the password, and collects the names or identifiers of rules that fail. Return a result object containing overall validity and the list of failures.
Define a configuration structure (e.g., object or map) that specifies which rules are active and their parameters (e.g., minLength, repeatLimit, specialChars). Provide sensible defaults and allow overrides.
Walk through test cases for each rule and combinations, including edge cases. Discuss trade-offs such as performance (O(n) per rule), extensibility, and whether to short-circuit or collect all failures.
AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.
Pretty straightforward once the code was written.
For each rule, systematically analyze the time and space complexity by identifying the input size and the operations performed. Express complexity in Big O notation, considering worst-case scenarios and any data structures used. Relate the complexity to the rule's purpose and discuss potential optimizations.
Pro tip: Always clarify the definition of 'n' (e.g., number of tokens, length of input) and mention that space complexity includes auxiliary space, not just input storage. This shows precision and avoids ambiguity.
State the rule clearly and define what constitutes the input size (e.g., number of tokens, length of string). This sets the context for complexity analysis.
Break down the rule into operations (loops, recursion, data structure accesses) and determine the worst-case time complexity in Big O notation.
Identify additional memory used (e.g., data structures, recursion stack) and express auxiliary space complexity in Big O notation.
Mention any trade-offs between time and space, and suggest possible optimizations or alternative implementations with better complexity.
AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.
This is where I slowed down more than I expected.
Start by clarifying the password validation rules and the testing framework to use. Then, systematically write unit tests for each specified boundary and condition, ensuring each test is independent and covers one scenario. Use parameterized tests for forbidden characters and character class omissions to reduce duplication.
Pro tip: Demonstrate maturity by discussing test naming conventions and the importance of testing edge cases like the 4th vs 5th occurrence, which often reveal off-by-one errors. Also, mention that you would run the tests to ensure they fail before implementing the validation logic (TDD).
Confirm the exact password rules (minimum length, forbidden characters, required character classes, and repetition limit) and the testing framework (e.g., JUnit, pytest). Set up the test file and necessary imports.
Write tests for passwords of length exactly the minimum (should pass) and one less than minimum (should fail). Also consider empty string and null if applicable.
For each forbidden character, write a test where the password contains that character and assert validation fails. Use parameterized tests to avoid repetition.
Write tests for a password with a character repeated 4 times (should pass) and 5 times (should fail), ensuring the repetition limit is enforced correctly.
For each required character class (e.g., uppercase, lowercase, digit, special), write a test where that class is missing and assert failure. Finally, write a test for a fully valid password that meets all criteria and assert success.
AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.