Check predecessor, revision, substring, and coverage snapshots

Choose the operation contract or failure response that matches each structure. Verify outputs against a direct reference model.

Lessons

• X-fast trie: predecessor and successor in a fixed integer universe
• Persistent radix vectors: copy one indexed path per revision
• Compressed suffix trees: locate patterns across a frozen text
• Disjoint interval unions: maintain covered maintenance time

Design exercise

• Project: audit predecessor, revision, substring, and coverage snapshots
• Data Structures