FA-94360 / Exam timetabling constraints / Member archive

Single exam in a period reported as a clash · case 05

Every scheduled sitting is listed as a clash.

Member previewVariant 5 · 3 implementations · 8 checks per implementation

Case contract

enrol rows [student, exam] (may repeat), period maps scheduled exams to a period, xlist groups cross-listed exams that are one physical paper (canonical name = smallest id in the group). A clash is a student with two or more distinct canonical papers in one period; unscheduled exams are ignored. Return [student, period, sorted papers] ordered by student then period.

Why this case matters

Clash detection is the primary hard constraint of exam timetabling; duplicate enrolments and cross-listing are the usual sources of false clashes.

One recorded failure

Sample boundary fixture

This sample comes from the broken implementation of a controlled reproducer.

Boundary fixture	Actual	Expected	Outcome
regression: clash threshold 1	`[["s1", 2, ["PHYS110"]], ["s1", 3, ["BIO130", "MATH101"]], ["s2", 2, ["ECON150", "PHYS110"]], ["s2", 3, ["BIO130"]], ["s3", 3, ["BIO130"]], ["s4", 2, ["PHYS110"]], ["s4", 3, ["MATH101"]], ["s5", 3, ["MATH101"]]]`	`[["s1", 3, ["BIO130", "MATH101"]], ["s2", 2, ["ECON150", "PHYS110"]]]`	Failed

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