Hash Map — Reasoning Check

1. An isomorphic-string scan sees its first pair p→q. Both maps are empty. What should it do?

Select one answer.

Reject because the default map value for p is not q. Install both directions; a missing key does not conflict with a new mapping. Install only p→q; a reverse lookup is needed only if p repeats.

2. For [8,8] and target 16, a correct single-pass Two Sum routine first finds a pair at which zero-based input index? Enter one integer.

3. A proposed Group Anagrams key is the sum of lowercase byte values. Why is it invalid?

Select one answer.

Reordering a word always changes the sum of its byte values. Different multisets such as "ad" and "bc" have the same sum. Equal words need different keys so that duplicate occurrences are retained.

4. What is the longest consecutive-sequence length in [10,5,6,5,8,9]? Enter one integer.

5. A longest-consecutive implementation builds a set, then loops over the ORIGINAL input. The input has M copies of 1 followed by 2 through M. What performance problem remains?

Select one answer.

Each copy of 1 can start the same length-M expansion, causing quadratic work. No problem remains because a set automatically deduplicates the outer input loop. Set construction itself must sort all values, causing quadratic work.

6. Can ransom note "baba" be constructed from magazine "aaabbc"? Enter true or false.