Cluster 5: Bridge to Computing

Attempt these four tasks before opening feedback. Keep a short contract, plan, argument or trace, and a looking-back note. These are the required P tasks; additional lesson drills are targeted repair or optional enrichment.

P17: Separate statuses

Design result types for a bounded path search distinguishing found, unreachable, unknown and invalid input. Give one concrete case for each.

P18: Specify time and identity

Write a deterministic filter-and-rank contract with explicit now and half-open 24-hour window. Include endpoint examples and duplicate-ID policy.

P19: Timebox a handoff

In a 30-minute exercise, investigate an aggregate that disagrees with a small source dataset. Preserve the initial hypothesis, two discriminating checks and a five-minute handoff. Report unresolved items honestly.

P20: Change an assumption

Reuse your coin-change work with at most one of each denomination. Give a case where the previous witness becomes invalid, a repaired state, and one unsupported claim you refuse to make.

Record assistance and reuse relevant lab evidence; do not duplicate the same work to satisfy several checklists.

For specification or verification repair, locate Dromey 1.5 using the book index. This is selective reinforcement, not an additional exercise quota.