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Used a hash set for the first string, then just checked membership while scanning the second.
Clarify the problem constraints (e.g., case sensitivity, character set, empty strings) and then propose an efficient solution using a hash set for O(n+m) time. Discuss trade-offs between different approaches and consider edge cases.
Pro tip: Demonstrate maturity by proactively discussing how to handle Unicode characters, as Pinterest operates globally and deals with international text. Also, mention that you would write unit tests for edge cases like empty strings and repeated characters.
Ask about case sensitivity, character encoding (ASCII vs Unicode), and whether the second string can be empty. Confirm that the function should return a boolean.
Decide between using a hash set, bit vector, or sorting. Explain that a hash set provides O(n+m) time and O(n) space, which is optimal for general cases.
Describe the steps: insert all characters of the first string into a set, then iterate through the second string and check if each character is in the set. Return false if any character is missing.
State time complexity O(n+m) and space complexity O(n) or O(min(n, alphabet size)). Compare with alternatives like sorting (O(n log n + m log m)) or brute force (O(n*m)).
Discuss empty strings, repeated characters, and Unicode. Mention that if the character set is small (e.g., ASCII), a boolean array or bit vector can be more space-efficient.
AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.