FAILURE MAP
← Case archive

FA-94596 / Exam timetabling constraints / Open access

Double-duty check shared across invigilators · case 01

Two different invigilators in the same period are reported as double-booked.

Verified by executionVariant 1 · 8 checks per implementationDownload source bundle ↓JSON ↗

ROOT CAUSE

The seen map is keyed by period only.

THE FAILURE

The seen map is keyed by period only.

Unsuccessful approach: Keying by invigilator and exam misses two different exams in one period.

Case contract

duties [invigilator, exam, period]; teach invigilator -> busy periods; subj invigilator -> subject code; exam subject is the part of the exam id before "-". Findings: busy (duty in a busy period), own_subject, double (same invigilator already on duty that period), daily_max (reported once, on the first duty that exceeds maxday on a day = period // spd). Return sorted [invigilator, exam, finding] rows.

Why this case matters

Invigilation rosters must respect teaching commitments, conflict-of-interest rules and daily limits.

1 / The failure

Exit 1
"""Failure Map reference implementation. Python standard library only."""
import json

N = 1
observations = []
def solve(duties, teach, subj, maxday, spd):
    out = []
    seen = {}
    per_day = {}
    for inv, ex, p in duties:
        if p in teach.get(inv, []):
            out.append([inv, ex, 'busy'])
        if ex.split('-')[0] == subj.get(inv):
            out.append([inv, ex, 'own_subject'])
        if p in seen:
            out.append([inv, ex, 'double'])
        seen[p] = ex
        d = (inv, p // spd)
        per_day[d] = per_day.get(d, 0) + 1
        if per_day[d] == maxday + 1:
            out.append([inv, ex, 'daily_max'])
    return sorted(out)
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[('regression: double duty key 1', [[['ann', 'MATH-101', 0], ['bob', 'CHEM-110', 0]], {}, {}, 2, 3], []),
  ('regression variant: double duty key 2',
   [[['ann', 'BIO-201', 2], ['bob', 'BIOL-300', 3], ['bob', 'BIOL-300', 4], ['ann', 'BIOL-300', 4],
     ['bob', 'CHEM-110', 1], ['ann', 'BIO-201', 1], ['cy', 'BIO-201', 2]],
    {'ann': [0], 'bob': [4, 5]}, {'ann': 'BIOL', 'bob': 'CHEM', 'cy': 'CHEM'}, 1, 3],
   [['ann', 'BIO-201', 'daily_max'], ['ann', 'BIOL-300', 'own_subject'], ['bob', 'BIOL-300', 'busy'],
    ['bob', 'BIOL-300', 'daily_max'], ['bob', 'CHEM-110', 'own_subject']]),
  ('partial repair guard 3',
   [[['ann', 'BIOL-300', 0], ['ann', 'BIO-201', 5], ['ann', 'MATH-101', 5], ['ann', 'BIO-201', 5]],
    {'ann': [], 'bob': [2, 3], 'cy': [0, 4]}, {'ann': 'CHEM', 'bob': 'BIO', 'cy': 'CHEM'}, 2, 2],
   [['ann', 'BIO-201', 'daily_max'], ['ann', 'BIO-201', 'double'], ['ann', 'MATH-101', 'double']]),
  ('boundary control 4', [[['ann', 'MATH-101', 2], ['ann', 'CHEM-110', 3]], {}, {}, 1, 3], []),
  ('normal control 5',
   [[['bob', 'MATH-101', 3], ['ann', 'BIOL-300', 2], ['cy', 'MATH-101', 1], ['cy', 'MATH-101', 5]],
    {'ann': [3, 5], 'cy': [0, 3]}, {'ann': 'BIOL', 'bob': 'BIOL', 'cy': 'BIOL'}, 2, 2],
   [['ann', 'BIOL-300', 'own_subject']]),
  ('normal control 6',
   [[['bob', 'CHEM-110', 5], ['ann', 'CHEM-110', 0]], {'ann': [], 'bob': [], 'cy': [1, 4]},
    {'ann': 'BIO', 'bob': 'CHEM', 'cy': 'BIOL'}, 1, 2],
   [['bob', 'CHEM-110', 'own_subject']]),
  ('normal control 7',
   [[['cy', 'BIOL-300', 1], ['ann', 'BIOL-300', 1], ['cy', 'CHEM-110', 1], ['bob', 'MATH-101', 5]],
    {'ann': [], 'cy': [0]}, {'ann': 'BIOL', 'bob': 'MATH', 'cy': 'MATH'}, 1, 2],
   [['ann', 'BIOL-300', 'own_subject'], ['bob', 'MATH-101', 'own_subject'], ['cy', 'CHEM-110', 'daily_max'],
    ['cy', 'CHEM-110', 'double']]),
  ('normal control 8',
   [[['ann', 'CHEM-110', 4], ['ann', 'BIO-201', 2]], {'ann': [3, 5], 'cy': []},
    {'ann': 'BIO', 'bob': 'MATH', 'cy': 'CHEM'}, 1, 2],
   [['ann', 'BIO-201', 'own_subject']])],
 [('regression: double duty key 1',
   [[['bob', 'BIOL-300', 3], ['bob', 'CHEM-110', 0], ['ann', 'CHEM-110', 0], ['cy', 'BIO-201', 4]],
    {'bob': [], 'cy': []}, {'ann': 'MATH', 'bob': 'BIOL', 'cy': 'BIOL'}, 2, 3],
   [['bob', 'BIOL-300', 'own_subject']]),
  ('regression variant: double duty key 2',
   [[['bob', 'BIO-201', 4], ['ann', 'BIOL-300', 5], ['cy', 'BIO-201', 5], ['ann', 'CHEM-110', 2]],
    {'ann': []}, {'ann': 'MATH', 'bob': 'CHEM', 'cy': 'CHEM'}, 1, 3],
   []),
  ('partial repair guard 3',
   [[['bob', 'BIOL-300', 3], ['cy', 'CHEM-110', 3], ['cy', 'CHEM-110', 3], ['ann', 'MATH-101', 0],
     ['bob', 'BIOL-300', 1], ['cy', 'MATH-101', 3]],
    {'bob': [], 'cy': [0, 2]}, {'ann': 'MATH', 'bob': 'CHEM', 'cy': 'BIO'}, 2, 3],
   [['ann', 'MATH-101', 'own_subject'], ['cy', 'CHEM-110', 'double'], ['cy', 'MATH-101', 'daily_max'],
    ['cy', 'MATH-101', 'double']]),
  ('boundary control 4', [[['ann', 'BIOL-300', 0]], {}, {'ann': 'BIO'}, 2, 3], []),
  ('normal control 5',
   [[['ann', 'BIOL-300', 0], ['bob', 'BIOL-300', 0], ['cy', 'CHEM-110', 2]], {'cy': [3, 4]},
    {'ann': 'CHEM', 'bob': 'BIO', 'cy': 'CHEM'}, 2, 3],
   [['cy', 'CHEM-110', 'own_subject']]),
  ('normal control 6',
   [[['cy', 'CHEM-110', 4], ['ann', 'BIO-201', 0], ['cy', 'BIO-201', 4], ['ann', 'MATH-101', 4],
     ['ann', 'BIO-201', 3]],
    {'ann': [1, 2], 'cy': []}, {'ann': 'BIO', 'bob': 'MATH', 'cy': 'BIOL'}, 1, 3],
   [['ann', 'BIO-201', 'daily_max'], ['ann', 'BIO-201', 'own_subject'], ['ann', 'BIO-201', 'own_subject'],
    ['cy', 'BIO-201', 'daily_max'], ['cy', 'BIO-201', 'double']]),
  ('normal control 7',
   [[['cy', 'BIOL-300', 3], ['ann', 'BIO-201', 4], ['ann', 'CHEM-110', 3], ['bob', 'BIO-201', 3],
     ['cy', 'BIOL-300', 1], ['bob', 'MATH-101', 4], ['cy', 'BIO-201', 0]],
    {'bob': [], 'cy': []}, {'ann': 'BIOL', 'bob': 'BIOL', 'cy': 'BIOL'}, 2, 3],
   [['cy', 'BIOL-300', 'own_subject'], ['cy', 'BIOL-300', 'own_subject']]),
  ('normal control 8',
   [[['bob', 'BIOL-300', 0], ['bob', 'BIOL-300', 3], ['cy', 'MATH-101', 2]],
    {'ann': [], 'bob': [2], 'cy': []}, {'ann': 'BIOL', 'bob': 'BIO', 'cy': 'MATH'}, 2, 2],
   [['cy', 'MATH-101', 'own_subject']])],
 [('regression: double duty key 1',
   [[['cy', 'MATH-101', 0], ['cy', 'BIOL-300', 0], ['ann', 'BIOL-300', 0], ['ann', 'BIO-201', 1],
     ['bob', 'BIO-201', 1]],
    {'bob': [1, 4], 'cy': []}, {'ann': 'BIO', 'bob': 'CHEM', 'cy': 'CHEM'}, 2, 2],
   [['ann', 'BIO-201', 'own_subject'], ['bob', 'BIO-201', 'busy'], ['cy', 'BIOL-300', 'double']]),
  ('regression variant: double duty key 2',
   [[['ann', 'MATH-101', 5], ['bob', 'MATH-101', 5], ['ann', 'BIO-201', 1], ['cy', 'CHEM-110', 3],
     ['bob', 'MATH-101', 2], ['cy', 'BIOL-300', 5], ['ann', 'BIO-201', 1]],
    {'ann': [], 'cy': [1, 2]}, {'ann': 'MATH', 'bob': 'CHEM', 'cy': 'BIO'}, 1, 3],
   [['ann', 'BIO-201', 'daily_max'], ['ann', 'BIO-201', 'double'], ['ann', 'MATH-101', 'own_subject'],
    ['cy', 'BIOL-300', 'daily_max']]),
  ('partial repair guard 3',
   [[['bob', 'BIOL-300', 0], ['ann', 'MATH-101', 5], ['bob', 'BIOL-300', 1]], {'ann': [], 'cy': [4]},
    {'ann': 'MATH', 'bob': 'MATH', 'cy': 'MATH'}, 1, 3],
   [['ann', 'MATH-101', 'own_subject'], ['bob', 'BIOL-300', 'daily_max']]),
  ('boundary control 4', [[['ann', 'MATH-101', 0], ['bob', 'CHEM-110', 0]], {}, {}, 2, 3], []),
  ('normal control 5',
   [[['ann', 'MATH-101', 1], ['ann', 'BIO-201', 2], ['bob', 'MATH-101', 4], ['cy', 'CHEM-110', 1],
     ['ann', 'MATH-101', 4], ['cy', 'MATH-101', 0], ['cy', 'CHEM-110', 4]],
    {'ann': [3], 'bob': [4]}, {'ann': 'CHEM', 'bob': 'MATH', 'cy': 'BIOL'}, 1, 2],
   [['bob', 'MATH-101', 'busy'], ['bob', 'MATH-101', 'own_subject'], ['cy', 'MATH-101', 'daily_max']]),
  ('normal control 6',
   [[['bob', 'BIO-201', 3], ['ann', 'BIOL-300', 4], ['ann', 'BIOL-300', 4], ['ann', 'BIO-201', 2],
     ['ann', 'MATH-101', 1], ['ann', 'BIOL-300', 0]],
    {'ann': [0], 'bob': [5], 'cy': []}, {'ann': 'BIOL', 'bob': 'BIO', 'cy': 'BIOL'}, 1, 3],
   [['ann', 'BIOL-300', 'busy'], ['ann', 'BIOL-300', 'daily_max'], ['ann', 'BIOL-300', 'double'],
    ['ann', 'BIOL-300', 'own_subject'], ['ann', 'BIOL-300', 'own_subject'],
    ['ann', 'BIOL-300', 'own_subject'], ['ann', 'MATH-101', 'daily_max'],
    ['bob', 'BIO-201', 'own_subject']]),
  ('normal control 7',
   [[['cy', 'BIO-201', 1], ['bob', 'BIO-201', 1], ['ann', 'BIO-201', 5]],
    {'ann': [3], 'bob': [0], 'cy': [3, 4]}, {'ann': 'CHEM', 'bob': 'MATH', 'cy': 'MATH'}, 2, 2],
   []),
  ('normal control 8',
   [[['ann', 'MATH-101', 0], ['bob', 'CHEM-110', 1]], {'ann': [], 'bob': [2], 'cy': []},
    {'ann': 'BIOL', 'bob': 'BIOL', 'cy': 'CHEM'}, 2, 2],
   [])],
 [('regression: double duty key 1',
   [[['bob', 'BIOL-300', 4], ['cy', 'CHEM-110', 5], ['cy', 'BIOL-300', 4], ['ann', 'CHEM-110', 4],
     ['ann', 'BIOL-300', 0], ['cy', 'CHEM-110', 5], ['cy', 'CHEM-110', 2]],
    {'ann': [], 'cy': [2]}, {'ann': 'MATH', 'bob': 'BIOL', 'cy': 'MATH'}, 2, 3],
   [['bob', 'BIOL-300', 'own_subject'], ['cy', 'CHEM-110', 'busy'], ['cy', 'CHEM-110', 'daily_max'],
    ['cy', 'CHEM-110', 'double']]),
  ('regression variant: double duty key 2',
   [[['bob', 'CHEM-110', 4], ['cy', 'CHEM-110', 1], ['ann', 'CHEM-110', 2], ['ann', 'BIOL-300', 5],
     ['bob', 'BIOL-300', 1]],
    {'ann': [], 'bob': [0], 'cy': [4, 5]}, {'ann': 'BIOL', 'bob': 'MATH', 'cy': 'MATH'}, 2, 3],
   [['ann', 'BIOL-300', 'own_subject']]),
  ('partial repair guard 3',
   [[['cy', 'BIO-201', 2], ['bob', 'BIOL-300', 3], ['ann', 'MATH-101', 3], ['ann', 'CHEM-110', 5],
     ['cy', 'MATH-101', 3], ['bob', 'BIOL-300', 0], ['cy', 'MATH-101', 0]],
    {'ann': [3], 'bob': [1, 2], 'cy': [5]}, {'ann': 'BIO', 'bob': 'MATH', 'cy': 'BIOL'}, 2, 2],
   [['ann', 'MATH-101', 'busy']]),
  ('boundary control 4',
   [[['ann', 'MATH-101', 0], ['ann', 'CHEM-110', 1], ['ann', 'BIO-201', 2]], {}, {}, 2, 3],
   [['ann', 'BIO-201', 'daily_max']]),
  ('normal control 5',
   [[['ann', 'BIO-201', 0], ['cy', 'BIOL-300', 0], ['cy', 'BIOL-300', 3], ['bob', 'BIO-201', 2],
     ['cy', 'BIO-201', 1], ['bob', 'BIO-201', 4], ['ann', 'CHEM-110', 0]],
    {'ann': [2], 'cy': []}, {'ann': 'CHEM', 'bob': 'CHEM', 'cy': 'MATH'}, 1, 2],
   [['ann', 'CHEM-110', 'daily_max'], ['ann', 'CHEM-110', 'double'], ['ann', 'CHEM-110', 'own_subject'],
    ['cy', 'BIO-201', 'daily_max']]),
  ('normal control 6',
   [[['bob', 'MATH-101', 1], ['cy', 'BIOL-300', 0], ['cy', 'MATH-101', 5], ['cy', 'CHEM-110', 1],
     ['cy', 'MATH-101', 4], ['bob', 'MATH-101', 0], ['bob', 'BIO-201', 3]],
    {'ann': [5], 'bob': [0, 2], 'cy': [2, 4]}, {'ann': 'CHEM', 'bob': 'CHEM', 'cy': 'BIO'}, 2, 2],
   [['bob', 'MATH-101', 'busy'], ['cy', 'MATH-101', 'busy']]),
  ('normal control 7',
   [[['bob', 'MATH-101', 2], ['bob', 'CHEM-110', 0], ['bob', 'BIOL-300', 0]],
    {'ann': [], 'bob': [1, 3], 'cy': []}, {'ann': 'BIOL', 'bob': 'BIOL', 'cy': 'BIOL'}, 1, 2],
   [['bob', 'BIOL-300', 'daily_max'], ['bob', 'BIOL-300', 'double'], ['bob', 'BIOL-300', 'own_subject']]),
  ('normal control 8',
   [[['ann', 'CHEM-110', 2], ['bob', 'BIOL-300', 3], ['cy', 'MATH-101', 2]], {'bob': [], 'cy': [0]},
    {'ann': 'CHEM', 'bob': 'CHEM', 'cy': 'MATH'}, 1, 2],
   [['ann', 'CHEM-110', 'own_subject'], ['cy', 'MATH-101', 'own_subject']])],
 [('regression: double duty key 1',
   [[['bob', 'BIO-201', 3], ['cy', 'CHEM-110', 5], ['ann', 'BIOL-300', 1], ['ann', 'BIO-201', 2],
     ['cy', 'CHEM-110', 3], ['bob', 'CHEM-110', 4], ['cy', 'CHEM-110', 0]],
    {'ann': [1, 5], 'bob': [3], 'cy': [3]}, {'ann': 'CHEM', 'bob': 'MATH', 'cy': 'MATH'}, 1, 3],
   [['ann', 'BIO-201', 'daily_max'], ['ann', 'BIOL-300', 'busy'], ['bob', 'BIO-201', 'busy'],
    ['bob', 'CHEM-110', 'daily_max'], ['cy', 'CHEM-110', 'busy'], ['cy', 'CHEM-110', 'daily_max']]),
  ('regression variant: double duty key 2',
   [[['ann', 'BIOL-300', 1], ['ann', 'MATH-101', 1], ['bob', 'CHEM-110', 0], ['ann', 'MATH-101', 5],
     ['ann', 'BIOL-300', 3], ['bob', 'BIO-201', 1]],
    {'ann': [1], 'bob': [0], 'cy': [0, 2]}, {'ann': 'CHEM', 'bob': 'BIOL', 'cy': 'CHEM'}, 2, 3],
   [['ann', 'BIOL-300', 'busy'], ['ann', 'MATH-101', 'busy'], ['ann', 'MATH-101', 'double'],
    ['bob', 'CHEM-110', 'busy']]),
  ('partial repair guard 3',
   [[['bob', 'BIOL-300', 2], ['bob', 'BIOL-300', 5], ['ann', 'BIOL-300', 4], ['ann', 'BIOL-300', 0]],
    {'ann': [], 'cy': []}, {'ann': 'BIOL', 'bob': 'CHEM', 'cy': 'BIOL'}, 1, 3],
   [['ann', 'BIOL-300', 'own_subject'], ['ann', 'BIOL-300', 'own_subject']]),
  ('boundary control 4', [[['ann', 'BIO-201', 0]], {}, {'ann': 'BIOL'}, 2, 3], []),
  ('normal control 5',
   [[['bob', 'MATH-101', 2], ['cy', 'CHEM-110', 1], ['cy', 'MATH-101', 2], ['cy', 'BIO-201', 5],
     ['cy', 'CHEM-110', 2], ['bob', 'BIO-201', 2], ['cy', 'BIOL-300', 3]],
    {'ann': [1, 5], 'bob': [2, 3], 'cy': [1, 2]}, {'ann': 'CHEM', 'bob': 'BIOL', 'cy': 'BIO'}, 2, 3],
   [['bob', 'BIO-201', 'busy'], ['bob', 'BIO-201', 'double'], ['bob', 'MATH-101', 'busy'],
    ['cy', 'BIO-201', 'own_subject'], ['cy', 'CHEM-110', 'busy'], ['cy', 'CHEM-110', 'busy'],
    ['cy', 'CHEM-110', 'daily_max'], ['cy', 'CHEM-110', 'double'], ['cy', 'MATH-101', 'busy']]),
  ('normal control 6',
   [[['ann', 'MATH-101', 1], ['bob', 'BIOL-300', 0], ['ann', 'MATH-101', 2], ['ann', 'MATH-101', 3],
     ['bob', 'BIOL-300', 4], ['bob', 'MATH-101', 4], ['ann', 'CHEM-110', 0]],
    {'ann': [], 'bob': [2, 5], 'cy': [1, 5]}, {'ann': 'CHEM', 'bob': 'CHEM', 'cy': 'BIOL'}, 2, 3],
   [['ann', 'CHEM-110', 'daily_max'], ['ann', 'CHEM-110', 'own_subject'], ['bob', 'MATH-101', 'double']]),
  ('normal control 7',
   [[['ann', 'BIO-201', 1], ['bob', 'BIOL-300', 0], ['cy', 'MATH-101', 2], ['bob', 'CHEM-110', 5]],
    {'ann': [0], 'bob': [1]}, {'ann': 'MATH', 'bob': 'MATH', 'cy': 'MATH'}, 1, 3],
   [['cy', 'MATH-101', 'own_subject']]),
  ('normal control 8',
   [[['ann', 'CHEM-110', 2], ['cy', 'MATH-101', 5], ['bob', 'BIOL-300', 2], ['cy', 'CHEM-110', 0],
     ['cy', 'CHEM-110', 4], ['ann', 'BIOL-300', 0], ['ann', 'CHEM-110', 4]],
    {'bob': [1, 2], 'cy': [0, 5]}, {'ann': 'BIOL', 'bob': 'BIOL', 'cy': 'CHEM'}, 1, 3],
   [['ann', 'BIOL-300', 'daily_max'], ['ann', 'BIOL-300', 'own_subject'], ['bob', 'BIOL-300', 'busy'],
    ['bob', 'BIOL-300', 'own_subject'], ['cy', 'CHEM-110', 'busy'], ['cy', 'CHEM-110', 'daily_max'],
    ['cy', 'CHEM-110', 'own_subject'], ['cy', 'CHEM-110', 'own_subject'], ['cy', 'MATH-101', 'busy']])]]
for label, args, expected in fixtures[N-1]:
    check(label, solve(*args), expected)
print(json.dumps({"observations": observations, "passed": all(x["passed"] for x in observations)}, ensure_ascii=False))
raise SystemExit(0 if all(x["passed"] for x in observations) else 1)
Boundary fixtureActualExpectedOutcome
regression: double duty key 1[['bob', 'CHEM-110', 'double']][]Failed
regression variant: double duty key 2[['ann', 'BIO-201', 'daily_max'], ['ann', 'BIO-201', 'double'], ['ann', 'BIOL-300', 'double'], ['ann', 'BIOL-300', 'own_subject'], ['bob', 'BIOL-300', 'busy'], ['bob', 'BIOL-300', 'daily_max'], ['bob', 'CHEM-110', 'own_subject'], ['cy', 'BIO-201', 'double']][['ann', 'BIO-201', 'daily_max'], ['ann', 'BIOL-300', 'own_subject'], ['bob', 'BIOL-300', 'busy'], ['bob', 'BIOL-300', 'daily_max'], ['bob', 'CHEM-110', 'own_subject']]Failed
partial repair guard 3[['ann', 'BIO-201', 'daily_max'], ['ann', 'BIO-201', 'double'], ['ann', 'MATH-101', 'double']][['ann', 'BIO-201', 'daily_max'], ['ann', 'BIO-201', 'double'], ['ann', 'MATH-101', 'double']]Passed
boundary control 4[][]Passed
normal control 5[['ann', 'BIOL-300', 'own_subject']][['ann', 'BIOL-300', 'own_subject']]Passed
normal control 6[['bob', 'CHEM-110', 'own_subject']][['bob', 'CHEM-110', 'own_subject']]Passed
normal control 7[['ann', 'BIOL-300', 'double'], ['ann', 'BIOL-300', 'own_subject'], ['bob', 'MATH-101', 'own_subject'], ['cy', 'CHEM-110', 'daily_max'], ['cy', 'CHEM-110', 'double']][['ann', 'BIOL-300', 'own_subject'], ['bob', 'MATH-101', 'own_subject'], ['cy', 'CHEM-110', 'daily_max'], ['cy', 'CHEM-110', 'double']]Failed
normal control 8[['ann', 'BIO-201', 'own_subject']][['ann', 'BIO-201', 'own_subject']]Passed

SHA-256 / 240fb15f8c6efca7d07ba2a7d6e18f521205074c410104ac820d138588e0ea93

2 / The unsuccessful fix

Exit 1
"""Failure Map reference implementation. Python standard library only."""
import json

N = 1
observations = []
def solve(duties, teach, subj, maxday, spd):
    out = []
    seen = {}
    per_day = {}
    for inv, ex, p in duties:
        if p in teach.get(inv, []):
            out.append([inv, ex, 'busy'])
        if ex.split('-')[0] == subj.get(inv):
            out.append([inv, ex, 'own_subject'])
        if (inv, ex) in seen:
            out.append([inv, ex, 'double'])
        seen[(inv, ex)] = ex
        d = (inv, p // spd)
        per_day[d] = per_day.get(d, 0) + 1
        if per_day[d] == maxday + 1:
            out.append([inv, ex, 'daily_max'])
    return sorted(out)
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[('regression: double duty key 1', [[['ann', 'MATH-101', 0], ['bob', 'CHEM-110', 0]], {}, {}, 2, 3], []),
  ('regression variant: double duty key 2',
   [[['ann', 'BIO-201', 2], ['bob', 'BIOL-300', 3], ['bob', 'BIOL-300', 4], ['ann', 'BIOL-300', 4],
     ['bob', 'CHEM-110', 1], ['ann', 'BIO-201', 1], ['cy', 'BIO-201', 2]],
    {'ann': [0], 'bob': [4, 5]}, {'ann': 'BIOL', 'bob': 'CHEM', 'cy': 'CHEM'}, 1, 3],
   [['ann', 'BIO-201', 'daily_max'], ['ann', 'BIOL-300', 'own_subject'], ['bob', 'BIOL-300', 'busy'],
    ['bob', 'BIOL-300', 'daily_max'], ['bob', 'CHEM-110', 'own_subject']]),
  ('partial repair guard 3',
   [[['ann', 'BIOL-300', 0], ['ann', 'BIO-201', 5], ['ann', 'MATH-101', 5], ['ann', 'BIO-201', 5]],
    {'ann': [], 'bob': [2, 3], 'cy': [0, 4]}, {'ann': 'CHEM', 'bob': 'BIO', 'cy': 'CHEM'}, 2, 2],
   [['ann', 'BIO-201', 'daily_max'], ['ann', 'BIO-201', 'double'], ['ann', 'MATH-101', 'double']]),
  ('boundary control 4', [[['ann', 'MATH-101', 2], ['ann', 'CHEM-110', 3]], {}, {}, 1, 3], []),
  ('normal control 5',
   [[['bob', 'MATH-101', 3], ['ann', 'BIOL-300', 2], ['cy', 'MATH-101', 1], ['cy', 'MATH-101', 5]],
    {'ann': [3, 5], 'cy': [0, 3]}, {'ann': 'BIOL', 'bob': 'BIOL', 'cy': 'BIOL'}, 2, 2],
   [['ann', 'BIOL-300', 'own_subject']]),
  ('normal control 6',
   [[['bob', 'CHEM-110', 5], ['ann', 'CHEM-110', 0]], {'ann': [], 'bob': [], 'cy': [1, 4]},
    {'ann': 'BIO', 'bob': 'CHEM', 'cy': 'BIOL'}, 1, 2],
   [['bob', 'CHEM-110', 'own_subject']]),
  ('normal control 7',
   [[['cy', 'BIOL-300', 1], ['ann', 'BIOL-300', 1], ['cy', 'CHEM-110', 1], ['bob', 'MATH-101', 5]],
    {'ann': [], 'cy': [0]}, {'ann': 'BIOL', 'bob': 'MATH', 'cy': 'MATH'}, 1, 2],
   [['ann', 'BIOL-300', 'own_subject'], ['bob', 'MATH-101', 'own_subject'], ['cy', 'CHEM-110', 'daily_max'],
    ['cy', 'CHEM-110', 'double']]),
  ('normal control 8',
   [[['ann', 'CHEM-110', 4], ['ann', 'BIO-201', 2]], {'ann': [3, 5], 'cy': []},
    {'ann': 'BIO', 'bob': 'MATH', 'cy': 'CHEM'}, 1, 2],
   [['ann', 'BIO-201', 'own_subject']])],
 [('regression: double duty key 1',
   [[['bob', 'BIOL-300', 3], ['bob', 'CHEM-110', 0], ['ann', 'CHEM-110', 0], ['cy', 'BIO-201', 4]],
    {'bob': [], 'cy': []}, {'ann': 'MATH', 'bob': 'BIOL', 'cy': 'BIOL'}, 2, 3],
   [['bob', 'BIOL-300', 'own_subject']]),
  ('regression variant: double duty key 2',
   [[['bob', 'BIO-201', 4], ['ann', 'BIOL-300', 5], ['cy', 'BIO-201', 5], ['ann', 'CHEM-110', 2]],
    {'ann': []}, {'ann': 'MATH', 'bob': 'CHEM', 'cy': 'CHEM'}, 1, 3],
   []),
  ('partial repair guard 3',
   [[['bob', 'BIOL-300', 3], ['cy', 'CHEM-110', 3], ['cy', 'CHEM-110', 3], ['ann', 'MATH-101', 0],
     ['bob', 'BIOL-300', 1], ['cy', 'MATH-101', 3]],
    {'bob': [], 'cy': [0, 2]}, {'ann': 'MATH', 'bob': 'CHEM', 'cy': 'BIO'}, 2, 3],
   [['ann', 'MATH-101', 'own_subject'], ['cy', 'CHEM-110', 'double'], ['cy', 'MATH-101', 'daily_max'],
    ['cy', 'MATH-101', 'double']]),
  ('boundary control 4', [[['ann', 'BIOL-300', 0]], {}, {'ann': 'BIO'}, 2, 3], []),
  ('normal control 5',
   [[['ann', 'BIOL-300', 0], ['bob', 'BIOL-300', 0], ['cy', 'CHEM-110', 2]], {'cy': [3, 4]},
    {'ann': 'CHEM', 'bob': 'BIO', 'cy': 'CHEM'}, 2, 3],
   [['cy', 'CHEM-110', 'own_subject']]),
  ('normal control 6',
   [[['cy', 'CHEM-110', 4], ['ann', 'BIO-201', 0], ['cy', 'BIO-201', 4], ['ann', 'MATH-101', 4],
     ['ann', 'BIO-201', 3]],
    {'ann': [1, 2], 'cy': []}, {'ann': 'BIO', 'bob': 'MATH', 'cy': 'BIOL'}, 1, 3],
   [['ann', 'BIO-201', 'daily_max'], ['ann', 'BIO-201', 'own_subject'], ['ann', 'BIO-201', 'own_subject'],
    ['cy', 'BIO-201', 'daily_max'], ['cy', 'BIO-201', 'double']]),
  ('normal control 7',
   [[['cy', 'BIOL-300', 3], ['ann', 'BIO-201', 4], ['ann', 'CHEM-110', 3], ['bob', 'BIO-201', 3],
     ['cy', 'BIOL-300', 1], ['bob', 'MATH-101', 4], ['cy', 'BIO-201', 0]],
    {'bob': [], 'cy': []}, {'ann': 'BIOL', 'bob': 'BIOL', 'cy': 'BIOL'}, 2, 3],
   [['cy', 'BIOL-300', 'own_subject'], ['cy', 'BIOL-300', 'own_subject']]),
  ('normal control 8',
   [[['bob', 'BIOL-300', 0], ['bob', 'BIOL-300', 3], ['cy', 'MATH-101', 2]],
    {'ann': [], 'bob': [2], 'cy': []}, {'ann': 'BIOL', 'bob': 'BIO', 'cy': 'MATH'}, 2, 2],
   [['cy', 'MATH-101', 'own_subject']])],
 [('regression: double duty key 1',
   [[['cy', 'MATH-101', 0], ['cy', 'BIOL-300', 0], ['ann', 'BIOL-300', 0], ['ann', 'BIO-201', 1],
     ['bob', 'BIO-201', 1]],
    {'bob': [1, 4], 'cy': []}, {'ann': 'BIO', 'bob': 'CHEM', 'cy': 'CHEM'}, 2, 2],
   [['ann', 'BIO-201', 'own_subject'], ['bob', 'BIO-201', 'busy'], ['cy', 'BIOL-300', 'double']]),
  ('regression variant: double duty key 2',
   [[['ann', 'MATH-101', 5], ['bob', 'MATH-101', 5], ['ann', 'BIO-201', 1], ['cy', 'CHEM-110', 3],
     ['bob', 'MATH-101', 2], ['cy', 'BIOL-300', 5], ['ann', 'BIO-201', 1]],
    {'ann': [], 'cy': [1, 2]}, {'ann': 'MATH', 'bob': 'CHEM', 'cy': 'BIO'}, 1, 3],
   [['ann', 'BIO-201', 'daily_max'], ['ann', 'BIO-201', 'double'], ['ann', 'MATH-101', 'own_subject'],
    ['cy', 'BIOL-300', 'daily_max']]),
  ('partial repair guard 3',
   [[['bob', 'BIOL-300', 0], ['ann', 'MATH-101', 5], ['bob', 'BIOL-300', 1]], {'ann': [], 'cy': [4]},
    {'ann': 'MATH', 'bob': 'MATH', 'cy': 'MATH'}, 1, 3],
   [['ann', 'MATH-101', 'own_subject'], ['bob', 'BIOL-300', 'daily_max']]),
  ('boundary control 4', [[['ann', 'MATH-101', 0], ['bob', 'CHEM-110', 0]], {}, {}, 2, 3], []),
  ('normal control 5',
   [[['ann', 'MATH-101', 1], ['ann', 'BIO-201', 2], ['bob', 'MATH-101', 4], ['cy', 'CHEM-110', 1],
     ['ann', 'MATH-101', 4], ['cy', 'MATH-101', 0], ['cy', 'CHEM-110', 4]],
    {'ann': [3], 'bob': [4]}, {'ann': 'CHEM', 'bob': 'MATH', 'cy': 'BIOL'}, 1, 2],
   [['bob', 'MATH-101', 'busy'], ['bob', 'MATH-101', 'own_subject'], ['cy', 'MATH-101', 'daily_max']]),
  ('normal control 6',
   [[['bob', 'BIO-201', 3], ['ann', 'BIOL-300', 4], ['ann', 'BIOL-300', 4], ['ann', 'BIO-201', 2],
     ['ann', 'MATH-101', 1], ['ann', 'BIOL-300', 0]],
    {'ann': [0], 'bob': [5], 'cy': []}, {'ann': 'BIOL', 'bob': 'BIO', 'cy': 'BIOL'}, 1, 3],
   [['ann', 'BIOL-300', 'busy'], ['ann', 'BIOL-300', 'daily_max'], ['ann', 'BIOL-300', 'double'],
    ['ann', 'BIOL-300', 'own_subject'], ['ann', 'BIOL-300', 'own_subject'],
    ['ann', 'BIOL-300', 'own_subject'], ['ann', 'MATH-101', 'daily_max'],
    ['bob', 'BIO-201', 'own_subject']]),
  ('normal control 7',
   [[['cy', 'BIO-201', 1], ['bob', 'BIO-201', 1], ['ann', 'BIO-201', 5]],
    {'ann': [3], 'bob': [0], 'cy': [3, 4]}, {'ann': 'CHEM', 'bob': 'MATH', 'cy': 'MATH'}, 2, 2],
   []),
  ('normal control 8',
   [[['ann', 'MATH-101', 0], ['bob', 'CHEM-110', 1]], {'ann': [], 'bob': [2], 'cy': []},
    {'ann': 'BIOL', 'bob': 'BIOL', 'cy': 'CHEM'}, 2, 2],
   [])],
 [('regression: double duty key 1',
   [[['bob', 'BIOL-300', 4], ['cy', 'CHEM-110', 5], ['cy', 'BIOL-300', 4], ['ann', 'CHEM-110', 4],
     ['ann', 'BIOL-300', 0], ['cy', 'CHEM-110', 5], ['cy', 'CHEM-110', 2]],
    {'ann': [], 'cy': [2]}, {'ann': 'MATH', 'bob': 'BIOL', 'cy': 'MATH'}, 2, 3],
   [['bob', 'BIOL-300', 'own_subject'], ['cy', 'CHEM-110', 'busy'], ['cy', 'CHEM-110', 'daily_max'],
    ['cy', 'CHEM-110', 'double']]),
  ('regression variant: double duty key 2',
   [[['bob', 'CHEM-110', 4], ['cy', 'CHEM-110', 1], ['ann', 'CHEM-110', 2], ['ann', 'BIOL-300', 5],
     ['bob', 'BIOL-300', 1]],
    {'ann': [], 'bob': [0], 'cy': [4, 5]}, {'ann': 'BIOL', 'bob': 'MATH', 'cy': 'MATH'}, 2, 3],
   [['ann', 'BIOL-300', 'own_subject']]),
  ('partial repair guard 3',
   [[['cy', 'BIO-201', 2], ['bob', 'BIOL-300', 3], ['ann', 'MATH-101', 3], ['ann', 'CHEM-110', 5],
     ['cy', 'MATH-101', 3], ['bob', 'BIOL-300', 0], ['cy', 'MATH-101', 0]],
    {'ann': [3], 'bob': [1, 2], 'cy': [5]}, {'ann': 'BIO', 'bob': 'MATH', 'cy': 'BIOL'}, 2, 2],
   [['ann', 'MATH-101', 'busy']]),
  ('boundary control 4',
   [[['ann', 'MATH-101', 0], ['ann', 'CHEM-110', 1], ['ann', 'BIO-201', 2]], {}, {}, 2, 3],
   [['ann', 'BIO-201', 'daily_max']]),
  ('normal control 5',
   [[['ann', 'BIO-201', 0], ['cy', 'BIOL-300', 0], ['cy', 'BIOL-300', 3], ['bob', 'BIO-201', 2],
     ['cy', 'BIO-201', 1], ['bob', 'BIO-201', 4], ['ann', 'CHEM-110', 0]],
    {'ann': [2], 'cy': []}, {'ann': 'CHEM', 'bob': 'CHEM', 'cy': 'MATH'}, 1, 2],
   [['ann', 'CHEM-110', 'daily_max'], ['ann', 'CHEM-110', 'double'], ['ann', 'CHEM-110', 'own_subject'],
    ['cy', 'BIO-201', 'daily_max']]),
  ('normal control 6',
   [[['bob', 'MATH-101', 1], ['cy', 'BIOL-300', 0], ['cy', 'MATH-101', 5], ['cy', 'CHEM-110', 1],
     ['cy', 'MATH-101', 4], ['bob', 'MATH-101', 0], ['bob', 'BIO-201', 3]],
    {'ann': [5], 'bob': [0, 2], 'cy': [2, 4]}, {'ann': 'CHEM', 'bob': 'CHEM', 'cy': 'BIO'}, 2, 2],
   [['bob', 'MATH-101', 'busy'], ['cy', 'MATH-101', 'busy']]),
  ('normal control 7',
   [[['bob', 'MATH-101', 2], ['bob', 'CHEM-110', 0], ['bob', 'BIOL-300', 0]],
    {'ann': [], 'bob': [1, 3], 'cy': []}, {'ann': 'BIOL', 'bob': 'BIOL', 'cy': 'BIOL'}, 1, 2],
   [['bob', 'BIOL-300', 'daily_max'], ['bob', 'BIOL-300', 'double'], ['bob', 'BIOL-300', 'own_subject']]),
  ('normal control 8',
   [[['ann', 'CHEM-110', 2], ['bob', 'BIOL-300', 3], ['cy', 'MATH-101', 2]], {'bob': [], 'cy': [0]},
    {'ann': 'CHEM', 'bob': 'CHEM', 'cy': 'MATH'}, 1, 2],
   [['ann', 'CHEM-110', 'own_subject'], ['cy', 'MATH-101', 'own_subject']])],
 [('regression: double duty key 1',
   [[['bob', 'BIO-201', 3], ['cy', 'CHEM-110', 5], ['ann', 'BIOL-300', 1], ['ann', 'BIO-201', 2],
     ['cy', 'CHEM-110', 3], ['bob', 'CHEM-110', 4], ['cy', 'CHEM-110', 0]],
    {'ann': [1, 5], 'bob': [3], 'cy': [3]}, {'ann': 'CHEM', 'bob': 'MATH', 'cy': 'MATH'}, 1, 3],
   [['ann', 'BIO-201', 'daily_max'], ['ann', 'BIOL-300', 'busy'], ['bob', 'BIO-201', 'busy'],
    ['bob', 'CHEM-110', 'daily_max'], ['cy', 'CHEM-110', 'busy'], ['cy', 'CHEM-110', 'daily_max']]),
  ('regression variant: double duty key 2',
   [[['ann', 'BIOL-300', 1], ['ann', 'MATH-101', 1], ['bob', 'CHEM-110', 0], ['ann', 'MATH-101', 5],
     ['ann', 'BIOL-300', 3], ['bob', 'BIO-201', 1]],
    {'ann': [1], 'bob': [0], 'cy': [0, 2]}, {'ann': 'CHEM', 'bob': 'BIOL', 'cy': 'CHEM'}, 2, 3],
   [['ann', 'BIOL-300', 'busy'], ['ann', 'MATH-101', 'busy'], ['ann', 'MATH-101', 'double'],
    ['bob', 'CHEM-110', 'busy']]),
  ('partial repair guard 3',
   [[['bob', 'BIOL-300', 2], ['bob', 'BIOL-300', 5], ['ann', 'BIOL-300', 4], ['ann', 'BIOL-300', 0]],
    {'ann': [], 'cy': []}, {'ann': 'BIOL', 'bob': 'CHEM', 'cy': 'BIOL'}, 1, 3],
   [['ann', 'BIOL-300', 'own_subject'], ['ann', 'BIOL-300', 'own_subject']]),
  ('boundary control 4', [[['ann', 'BIO-201', 0]], {}, {'ann': 'BIOL'}, 2, 3], []),
  ('normal control 5',
   [[['bob', 'MATH-101', 2], ['cy', 'CHEM-110', 1], ['cy', 'MATH-101', 2], ['cy', 'BIO-201', 5],
     ['cy', 'CHEM-110', 2], ['bob', 'BIO-201', 2], ['cy', 'BIOL-300', 3]],
    {'ann': [1, 5], 'bob': [2, 3], 'cy': [1, 2]}, {'ann': 'CHEM', 'bob': 'BIOL', 'cy': 'BIO'}, 2, 3],
   [['bob', 'BIO-201', 'busy'], ['bob', 'BIO-201', 'double'], ['bob', 'MATH-101', 'busy'],
    ['cy', 'BIO-201', 'own_subject'], ['cy', 'CHEM-110', 'busy'], ['cy', 'CHEM-110', 'busy'],
    ['cy', 'CHEM-110', 'daily_max'], ['cy', 'CHEM-110', 'double'], ['cy', 'MATH-101', 'busy']]),
  ('normal control 6',
   [[['ann', 'MATH-101', 1], ['bob', 'BIOL-300', 0], ['ann', 'MATH-101', 2], ['ann', 'MATH-101', 3],
     ['bob', 'BIOL-300', 4], ['bob', 'MATH-101', 4], ['ann', 'CHEM-110', 0]],
    {'ann': [], 'bob': [2, 5], 'cy': [1, 5]}, {'ann': 'CHEM', 'bob': 'CHEM', 'cy': 'BIOL'}, 2, 3],
   [['ann', 'CHEM-110', 'daily_max'], ['ann', 'CHEM-110', 'own_subject'], ['bob', 'MATH-101', 'double']]),
  ('normal control 7',
   [[['ann', 'BIO-201', 1], ['bob', 'BIOL-300', 0], ['cy', 'MATH-101', 2], ['bob', 'CHEM-110', 5]],
    {'ann': [0], 'bob': [1]}, {'ann': 'MATH', 'bob': 'MATH', 'cy': 'MATH'}, 1, 3],
   [['cy', 'MATH-101', 'own_subject']]),
  ('normal control 8',
   [[['ann', 'CHEM-110', 2], ['cy', 'MATH-101', 5], ['bob', 'BIOL-300', 2], ['cy', 'CHEM-110', 0],
     ['cy', 'CHEM-110', 4], ['ann', 'BIOL-300', 0], ['ann', 'CHEM-110', 4]],
    {'bob': [1, 2], 'cy': [0, 5]}, {'ann': 'BIOL', 'bob': 'BIOL', 'cy': 'CHEM'}, 1, 3],
   [['ann', 'BIOL-300', 'daily_max'], ['ann', 'BIOL-300', 'own_subject'], ['bob', 'BIOL-300', 'busy'],
    ['bob', 'BIOL-300', 'own_subject'], ['cy', 'CHEM-110', 'busy'], ['cy', 'CHEM-110', 'daily_max'],
    ['cy', 'CHEM-110', 'own_subject'], ['cy', 'CHEM-110', 'own_subject'], ['cy', 'MATH-101', 'busy']])]]
for label, args, expected in fixtures[N-1]:
    check(label, solve(*args), expected)
print(json.dumps({"observations": observations, "passed": all(x["passed"] for x in observations)}, ensure_ascii=False))
raise SystemExit(0 if all(x["passed"] for x in observations) else 1)
Boundary fixtureActualExpectedOutcome
regression: double duty key 1[][]Passed
regression variant: double duty key 2[['ann', 'BIO-201', 'daily_max'], ['ann', 'BIO-201', 'double'], ['ann', 'BIOL-300', 'own_subject'], ['bob', 'BIOL-300', 'busy'], ['bob', 'BIOL-300', 'daily_max'], ['bob', 'BIOL-300', 'double'], ['bob', 'CHEM-110', 'own_subject']][['ann', 'BIO-201', 'daily_max'], ['ann', 'BIOL-300', 'own_subject'], ['bob', 'BIOL-300', 'busy'], ['bob', 'BIOL-300', 'daily_max'], ['bob', 'CHEM-110', 'own_subject']]Failed
partial repair guard 3[['ann', 'BIO-201', 'daily_max'], ['ann', 'BIO-201', 'double']][['ann', 'BIO-201', 'daily_max'], ['ann', 'BIO-201', 'double'], ['ann', 'MATH-101', 'double']]Failed
boundary control 4[][]Passed
normal control 5[['ann', 'BIOL-300', 'own_subject'], ['cy', 'MATH-101', 'double']][['ann', 'BIOL-300', 'own_subject']]Failed
normal control 6[['bob', 'CHEM-110', 'own_subject']][['bob', 'CHEM-110', 'own_subject']]Passed
normal control 7[['ann', 'BIOL-300', 'own_subject'], ['bob', 'MATH-101', 'own_subject'], ['cy', 'CHEM-110', 'daily_max']][['ann', 'BIOL-300', 'own_subject'], ['bob', 'MATH-101', 'own_subject'], ['cy', 'CHEM-110', 'daily_max'], ['cy', 'CHEM-110', 'double']]Failed
normal control 8[['ann', 'BIO-201', 'own_subject']][['ann', 'BIO-201', 'own_subject']]Passed

SHA-256 / 04b77351b7cbbd52f6ec5661fd14da11151fb69464784fe811594eb9e0e31e2f

HELD IN THE MEMBER ARCHIVE

The verified repair and its recorded checks are member-only.

This mechanism has 8 recorded checks per implementation. The open-access tier publishes the failure and the unsuccessful fix; the repaired source that passes every check, and the observations that prove it, are available to members.

Every case sharing this mechanism uses the same contract and the same repair, so this one record is held back for all of them.

Member access is invitation-based. Sign in with your invited account to inspect the repair.

Sign in to the archive ↗

Verification & scope

Stipulated toy exam-timetabling rule set for a bounded model; it does not claim conformance with any institution's regulations or a benchmark specification, and it performs no search or optimisation. This reproducer isolates one failure mechanism. Results cover the supplied fixtures. Variants within a family share a test contract and should remain grouped when constructing evaluation splits. Related mechanisms with a shared evaluation_group must also remain together; these controlled models are not independent production incidents.

Observations recorded using Python 3.12.14 at 2026-09-29T14:52:05.877141+00:00.

Case digest / 22a7918c8a12e5a6cfa495571c2da20142b0abdbd352a5aee71c6b86115b587a