← Anthropic Interview Insights
Model the problem as a graph where each email is a node and accounts are connected if they share an email. Use union-find (disjoint set union) to efficiently merge accounts, then group emails by their root representative. Alternatively, use DFS/BFS on the graph, but union-find is more efficient for this merging task.
Pro tip: Mention that the order of emails within each merged account doesn't matter, but you should sort them for consistent output. Also, clarify that the name can be taken from any account in the merged set, as names are assumed consistent for the same person.
Ask about input size, whether names are consistent for the same person, and if the output order matters. Confirm that accounts with the same name but no shared emails should not be merged.
Use a hash map to map each email to an account index or directly to a union-find parent. Use union-find to track connected components of accounts.
Iterate through each account and its emails. For each email, if it's seen before, union the current account with the account that first contained that email. Otherwise, record the email's owner.
After processing all accounts, traverse the union-find to find the root for each account. Collect all emails for each root into a set to deduplicate, and pick a name (e.g., the first account's name).
For each root, create a list with the name followed by the sorted list of unique emails. Return the list of merged accounts.
AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.