Pretty clean to code once you think through the edge cases.
Use a two-pointer technique to traverse the word and abbreviation simultaneously. When encountering a digit in the abbreviation, parse the full number (ensuring no leading zeros) and skip that many characters in the word. At the end, both pointers should have reached the end of their respective strings.
Pro tip: Clarify edge cases upfront: empty strings, abbreviation with only numbers, and numbers with leading zeros. Also, consider using a single pass with careful index management to avoid off-by-one errors.
Confirm that leading zeros are invalid, numbers represent skips, and both strings may be empty. Discuss examples like 'a' vs '1' (valid) and 'a' vs '01' (invalid).
Set pointers i for word and j for abbreviation, both starting at 0. Plan to iterate until both reach the end.
While j < len(abbr): if abbr[j] is a digit, parse the number (check for leading zero), advance i by that number; else, compare characters and advance both pointers.
After the loop, ensure both i and j have reached the end of their strings. If not, return false.
Run through cases like empty strings, all-digit abbreviations, and mismatched lengths to verify correctness.
AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.
Model the problem as a two-pointer scan over the abbreviations, where each pointer can either match the current character or skip it. Use recursion with memoization to avoid exponential recomputation, and reconstruct the alignment by storing decisions. Return true as soon as a valid alignment is found, and backtrack to output one alignment.
Pro tip: Clarify whether the abbreviations are case-sensitive and whether they must represent the same word or can represent different words. Also, mention that the problem is equivalent to finding a common subsequence of the two abbreviations, which can be solved in O(n*m) time with DP.
Ask if the abbreviations are case-sensitive, if they must represent the same word, and if the word must be a valid English word or any string. Confirm that we need to return one alignment if it exists.
Let i and j be indices into the two abbreviations. At each step, we can either match the current characters (if they are equal) and advance both, or skip a character in one abbreviation and advance only that pointer.
Create a memo table to store whether a solution exists from state (i, j). Use recursion to explore match and skip options, caching results to avoid recomputation. Time complexity O(n*m).
During recursion, store the choice made at each state (match, skip first, skip second). Once a solution is found, backtrack from (0,0) to build the alignment of kept vs skipped positions.
If a solution exists, return true and the alignment; otherwise return false. Discuss edge cases like empty strings and no common characters.
AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.
Start by clearly stating the time and space complexity of your solution using Big-O notation, then explain how you would adapt it for long inputs or streaming by discussing trade-offs between memory and time, and proposing techniques like chunking, sliding windows, or external sorting. Emphasize that the adaptation depends on the specific constraints and validation requirements.
Pro tip: Demonstrate awareness of real-world constraints by mentioning that streaming validation often requires a shift from batch processing to incremental algorithms, and that you would consider probabilistic data structures like Bloom filters when exact answers are not feasible.
Clearly articulate the time and space complexity of your original solution, specifying the variables (e.g., n = input size) and whether it's average or worst case.
Discuss which parts of your solution scale poorly with input size, such as memory usage for storing the entire input or time complexity that grows superlinearly.
Suggest modifications like processing input in chunks, using a sliding window, or maintaining only necessary state to achieve O(1) or O(k) space where k is small.
Explain how streaming might affect correctness (e.g., approximate results) and how you would handle validation, such as early termination or incremental checks.
Conclude by recommending a specific approach based on typical constraints, and mention any additional considerations like parallelism or external storage.
AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.