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FA-95241 / Warehouse slotting and bin packing / Open access

Pick sequence: last aisle rejected · case 01

Locations in aisle 40 are rejected as invalid.

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

ROOT CAUSE

The aisle upper bound excludes 40.

THE FAILURE

The aisle upper bound excludes 40.

Unsuccessful approach: Opening the lower bound accepts aisle 0, which does not exist.

Case contract

codes "aisle-bay-level" with decimal parts and optional surrounding whitespace. Valid aisles 1-40, levels 1-6. Canonical form "AA-BB-L" (two-digit aisle and bay). Duplicates collapse. Sequence: aisles ascending; odd aisles walk bays ascending, even aisles descending; level ascending within a bay. Invalid codes are returned as given, sorted, duplicates kept. Return [sequence, invalid].

Why this case matters

Pick paths are sequenced from location codes in a serpentine walk.

1 / The failure

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

N = 1
observations = []
def solve(codes):
    seq = {}
    bad = []
    for code in codes:
        parts = code.strip().split('-')
        if len(parts) != 3 or not all(p.isdecimal() for p in parts):
            bad.append(code)
            continue
        a, b, l = (int(p) for p in parts)
        if not (1 <= a < 40 and 1 <= l <= 6):
            bad.append(code)
            continue
        seq[(a, b, l)] = '%02d-%02d-%d' % (a, b, l)
    def walk(k):
        a, b, l = k
        return (a, b if a % 2 == 1 else -b, l)
    return [[seq[k] for k in sorted(seq, key=walk)], sorted(bad)]
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[['range limits', [['40-1-6', '41-1-1', '1-1-7', '0-1-1']], [['40-01-6'], ['0-1-1', '1-1-7', '41-1-1']]], ['generated mix 3', [['\t1 -05-2\n', '\t0 -1-1 ', '0-7-6', '40 -1-7']], [[], ['\t0 -1-1 ', '\t1 -05-2\n', '0-7-6', '40 -1-7']]], ['serpentine', [['2-01-1', '1-05-1', '2-09-1', '1-02-1']], [['01-02-1', '01-05-1', '02-09-1', '02-01-1'], []]], ['whitespace', [[' 1-1-1\n', '\t1-2-1']], [['01-01-1', '01-02-1'], []]], ['dup invalid kept', [['B', 'A', 'B']], [[], ['A', 'B', 'B']]], ['levels ascend', [['3-4-2', '3-4-1']], [['03-04-1', '03-04-2'], []]], ['generated mix 7', [['\t2-05-0', '\t3-7-2\n', 'X 0-7-0', ' 01-05-7', 'X 2-7-0 ', '\t01-12-2', '1-12-7 ']], [['01-12-2', '03-07-2'], ['\t2-05-0', ' 01-05-7', '1-12-7 ', 'X 0-7-0', 'X 2-7-0 ']]], ['generated mix 15', [['\t41-12-2', ' 40-1-2 ', '\t2-7-1\n']], [['02-07-1', '40-01-2'], ['\t41-12-2']]]], [['generated mix 27', [['40-7-1', '03-05-6\n', '\t1 -12-6', '\t2-7-7 ', 'X\t2-05-0']], [['03-05-6', '40-07-1'], ['\t1 -12-6', '\t2-7-7 ', 'X\t2-05-0']]], ['generated mix 37', [['0-12-2\n', '02-7-6', '2-7-6 ', ' 1-05-2', '\t40-12-0', '\t1-12-2\n', '01-7-6 ']], [['01-05-2', '01-07-6', '01-12-2', '02-07-6'], ['\t40-12-0', '0-12-2\n']]], ['inner space invalid', [['1 -1-1', '1-1-1']], [['01-01-1'], ['1 -1-1']]], ['dup invalid kept', [['B', 'A', 'B']], [[], ['A', 'B', 'B']]], ['serpentine', [['2-01-1', '1-05-1', '2-09-1', '1-02-1']], [['01-02-1', '01-05-1', '02-09-1', '02-01-1'], []]], ['whitespace', [[' 1-1-1\n', '\t1-2-1']], [['01-01-1', '01-02-1'], []]], ['generated mix 9', [['2-7-1', '2-1-2', '1-12-2\n']], [['01-12-2', '02-07-1', '02-01-2'], []]], ['generated mix 17', [['\t02-7-1', ' 2-12-2', '03-12-2']], [['02-12-2', '02-07-1', '03-12-2'], []]]], [['generated mix 60', [['0-12-7', '\t01-7-1', '\t01-1-1\n', ' 40-7-1 ', 'X1-05-0\n']], [['01-01-1', '01-07-1', '40-07-1'], ['0-12-7', 'X1-05-0\n']]], ['generated mix 61', [['\t1-7-1', ' 41-1-0\n', '\t0-1-1', '2-1-7 ', '03 -7-1', '3-1-0']], [['01-07-1'], ['\t0-1-1', ' 41-1-0\n', '03 -7-1', '2-1-7 ', '3-1-0']]], ['dedupe canonical', [['01-01-1', '1-1-1']], [['01-01-1'], []]], ['levels ascend', [['3-4-2', '3-4-1']], [['03-04-1', '03-04-2'], []]], ['inner space invalid', [['1 -1-1', '1-1-1']], [['01-01-1'], ['1 -1-1']]], ['dup invalid kept', [['B', 'A', 'B']], [[], ['A', 'B', 'B']]], ['generated mix 20', [['03-7-0', ' 40-7-0 ']], [[], [' 40-7-0 ', '03-7-0']]], ['generated mix 28', [['\t41-12-1\n', ' 2-12-2\n', '0-1-6 ', 'X\t1-05-7 ', ' 1 -12-6\n']], [['02-12-2'], ['\t41-12-1\n', ' 1 -12-6\n', '0-1-6 ', 'X\t1-05-7 ']]]], [['generated mix 14', [['1-1-1 ', ' 1-1-7\n', '\t40-12-6', '\t2-1-1', ' 1-1-7\n', '40-05-2 ', '01-1-7 ']], [['01-01-1', '02-01-1', '40-12-6', '40-05-2'], [' 1-1-7\n', ' 1-1-7\n', '01-1-7 ']]], ['generated mix 22', [[' 0-12-1', '3-12-0 ', 'X 01-7-1\n', '\t3-7-6 ', '3-12-1', ' 40-12-6 ', '\t03-7-7']], [['03-07-6', '03-12-1', '40-12-6'], ['\t03-7-7', ' 0-12-1', '3-12-0 ', 'X 01-7-1\n']]], ['whitespace', [[' 1-1-1\n', '\t1-2-1']], [['01-01-1', '01-02-1'], []]], ['range limits', [['40-1-6', '41-1-1', '1-1-7', '0-1-1']], [['40-01-6'], ['0-1-1', '1-1-7', '41-1-1']]], ['dedupe canonical', [['01-01-1', '1-1-1']], [['01-01-1'], []]], ['levels ascend', [['3-4-2', '3-4-1']], [['03-04-1', '03-04-2'], []]], ['generated mix 33', [[' 01-1-2\n', ' 1-05-1 ', '\t01-12-7\n', ' 41-7-7 ', ' 41-1-6\n']], [['01-01-2', '01-05-1'], ['\t01-12-7\n', ' 41-1-6\n', ' 41-7-7 ']]], ['generated mix 41', [[' 2-12-1 ', '40-7-1\n', '\t03-1-2\n', '\t40-1-6\n', '01-7-6', '\t1-7-0\n']], [['01-07-6', '02-12-1', '03-01-2', '40-07-1', '40-01-6'], ['\t1-7-0\n']]]], [['generated mix 41', [[' 2-12-1 ', '40-7-1\n', '\t03-1-2\n', '\t40-1-6\n', '01-7-6', '\t1-7-0\n']], [['01-07-6', '02-12-1', '03-01-2', '40-07-1', '40-01-6'], ['\t1-7-0\n']]], ['generated mix 42', [['40-12-0\n', 'X 40-12-7', '\t02-7-2', ' 3-12-6\n', '40-05-2\n', ' 41-12-2 ', '0-7-2\n']], [['02-07-2', '03-12-6', '40-05-2'], [' 41-12-2 ', '0-7-2\n', '40-12-0\n', 'X 40-12-7']]], ['dup invalid kept', [['B', 'A', 'B']], [[], ['A', 'B', 'B']]], ['serpentine', [['2-01-1', '1-05-1', '2-09-1', '1-02-1']], [['01-02-1', '01-05-1', '02-09-1', '02-01-1'], []]], ['whitespace', [[' 1-1-1\n', '\t1-2-1']], [['01-01-1', '01-02-1'], []]], ['range limits', [['40-1-6', '41-1-1', '1-1-7', '0-1-1']], [['40-01-6'], ['0-1-1', '1-1-7', '41-1-1']]], ['generated mix 44', [['\t3 -12-2\n', ' 3-1-7', ' 40-7-6\n']], [['40-07-6'], ['\t3 -12-2\n', ' 3-1-7']]], ['generated mix 52', [['1-1-7', '1-05-6', '03-7-2', '\t1-12-2 ', 'X\t0-7-2 ', '40-1-7', '\t1 -05-1 ']], [['01-05-6', '01-12-2', '03-07-2'], ['\t1 -05-1 ', '1-1-7', '40-1-7', 'X\t0-7-2 ']]]]]
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
range limits[[], ['0-1-1', '1-1-7', '40-1-6', '41-1-1']][['40-01-6'], ['0-1-1', '1-1-7', '41-1-1']]Failed
generated mix 3[[], ['\t0 -1-1 ', '\t1 -05-2\n', '0-7-6', '40 -1-7']][[], ['\t0 -1-1 ', '\t1 -05-2\n', '0-7-6', '40 -1-7']]Passed
serpentine[['01-02-1', '01-05-1', '02-09-1', '02-01-1'], []][['01-02-1', '01-05-1', '02-09-1', '02-01-1'], []]Passed
whitespace[['01-01-1', '01-02-1'], []][['01-01-1', '01-02-1'], []]Passed
dup invalid kept[[], ['A', 'B', 'B']][[], ['A', 'B', 'B']]Passed
levels ascend[['03-04-1', '03-04-2'], []][['03-04-1', '03-04-2'], []]Passed
generated mix 7[['01-12-2', '03-07-2'], ['\t2-05-0', ' 01-05-7', '1-12-7 ', 'X 0-7-0', 'X 2-7-0 ']][['01-12-2', '03-07-2'], ['\t2-05-0', ' 01-05-7', '1-12-7 ', 'X 0-7-0', 'X 2-7-0 ']]Passed
generated mix 15[['02-07-1'], ['\t41-12-2', ' 40-1-2 ']][['02-07-1', '40-01-2'], ['\t41-12-2']]Failed

SHA-256 / bc410839bb8f6615c6dac9d15de950fd9052d0522633334eaffedec7aa39bbff

2 / The unsuccessful fix

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

N = 1
observations = []
def solve(codes):
    seq = {}
    bad = []
    for code in codes:
        parts = code.strip().split('-')
        if len(parts) != 3 or not all(p.isdecimal() for p in parts):
            bad.append(code)
            continue
        a, b, l = (int(p) for p in parts)
        if not (0 <= a <= 40 and 1 <= l <= 6):
            bad.append(code)
            continue
        seq[(a, b, l)] = '%02d-%02d-%d' % (a, b, l)
    def walk(k):
        a, b, l = k
        return (a, b if a % 2 == 1 else -b, l)
    return [[seq[k] for k in sorted(seq, key=walk)], sorted(bad)]
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[['range limits', [['40-1-6', '41-1-1', '1-1-7', '0-1-1']], [['40-01-6'], ['0-1-1', '1-1-7', '41-1-1']]], ['generated mix 3', [['\t1 -05-2\n', '\t0 -1-1 ', '0-7-6', '40 -1-7']], [[], ['\t0 -1-1 ', '\t1 -05-2\n', '0-7-6', '40 -1-7']]], ['serpentine', [['2-01-1', '1-05-1', '2-09-1', '1-02-1']], [['01-02-1', '01-05-1', '02-09-1', '02-01-1'], []]], ['whitespace', [[' 1-1-1\n', '\t1-2-1']], [['01-01-1', '01-02-1'], []]], ['dup invalid kept', [['B', 'A', 'B']], [[], ['A', 'B', 'B']]], ['levels ascend', [['3-4-2', '3-4-1']], [['03-04-1', '03-04-2'], []]], ['generated mix 7', [['\t2-05-0', '\t3-7-2\n', 'X 0-7-0', ' 01-05-7', 'X 2-7-0 ', '\t01-12-2', '1-12-7 ']], [['01-12-2', '03-07-2'], ['\t2-05-0', ' 01-05-7', '1-12-7 ', 'X 0-7-0', 'X 2-7-0 ']]], ['generated mix 15', [['\t41-12-2', ' 40-1-2 ', '\t2-7-1\n']], [['02-07-1', '40-01-2'], ['\t41-12-2']]]], [['generated mix 27', [['40-7-1', '03-05-6\n', '\t1 -12-6', '\t2-7-7 ', 'X\t2-05-0']], [['03-05-6', '40-07-1'], ['\t1 -12-6', '\t2-7-7 ', 'X\t2-05-0']]], ['generated mix 37', [['0-12-2\n', '02-7-6', '2-7-6 ', ' 1-05-2', '\t40-12-0', '\t1-12-2\n', '01-7-6 ']], [['01-05-2', '01-07-6', '01-12-2', '02-07-6'], ['\t40-12-0', '0-12-2\n']]], ['inner space invalid', [['1 -1-1', '1-1-1']], [['01-01-1'], ['1 -1-1']]], ['dup invalid kept', [['B', 'A', 'B']], [[], ['A', 'B', 'B']]], ['serpentine', [['2-01-1', '1-05-1', '2-09-1', '1-02-1']], [['01-02-1', '01-05-1', '02-09-1', '02-01-1'], []]], ['whitespace', [[' 1-1-1\n', '\t1-2-1']], [['01-01-1', '01-02-1'], []]], ['generated mix 9', [['2-7-1', '2-1-2', '1-12-2\n']], [['01-12-2', '02-07-1', '02-01-2'], []]], ['generated mix 17', [['\t02-7-1', ' 2-12-2', '03-12-2']], [['02-12-2', '02-07-1', '03-12-2'], []]]], [['generated mix 60', [['0-12-7', '\t01-7-1', '\t01-1-1\n', ' 40-7-1 ', 'X1-05-0\n']], [['01-01-1', '01-07-1', '40-07-1'], ['0-12-7', 'X1-05-0\n']]], ['generated mix 61', [['\t1-7-1', ' 41-1-0\n', '\t0-1-1', '2-1-7 ', '03 -7-1', '3-1-0']], [['01-07-1'], ['\t0-1-1', ' 41-1-0\n', '03 -7-1', '2-1-7 ', '3-1-0']]], ['dedupe canonical', [['01-01-1', '1-1-1']], [['01-01-1'], []]], ['levels ascend', [['3-4-2', '3-4-1']], [['03-04-1', '03-04-2'], []]], ['inner space invalid', [['1 -1-1', '1-1-1']], [['01-01-1'], ['1 -1-1']]], ['dup invalid kept', [['B', 'A', 'B']], [[], ['A', 'B', 'B']]], ['generated mix 20', [['03-7-0', ' 40-7-0 ']], [[], [' 40-7-0 ', '03-7-0']]], ['generated mix 28', [['\t41-12-1\n', ' 2-12-2\n', '0-1-6 ', 'X\t1-05-7 ', ' 1 -12-6\n']], [['02-12-2'], ['\t41-12-1\n', ' 1 -12-6\n', '0-1-6 ', 'X\t1-05-7 ']]]], [['generated mix 14', [['1-1-1 ', ' 1-1-7\n', '\t40-12-6', '\t2-1-1', ' 1-1-7\n', '40-05-2 ', '01-1-7 ']], [['01-01-1', '02-01-1', '40-12-6', '40-05-2'], [' 1-1-7\n', ' 1-1-7\n', '01-1-7 ']]], ['generated mix 22', [[' 0-12-1', '3-12-0 ', 'X 01-7-1\n', '\t3-7-6 ', '3-12-1', ' 40-12-6 ', '\t03-7-7']], [['03-07-6', '03-12-1', '40-12-6'], ['\t03-7-7', ' 0-12-1', '3-12-0 ', 'X 01-7-1\n']]], ['whitespace', [[' 1-1-1\n', '\t1-2-1']], [['01-01-1', '01-02-1'], []]], ['range limits', [['40-1-6', '41-1-1', '1-1-7', '0-1-1']], [['40-01-6'], ['0-1-1', '1-1-7', '41-1-1']]], ['dedupe canonical', [['01-01-1', '1-1-1']], [['01-01-1'], []]], ['levels ascend', [['3-4-2', '3-4-1']], [['03-04-1', '03-04-2'], []]], ['generated mix 33', [[' 01-1-2\n', ' 1-05-1 ', '\t01-12-7\n', ' 41-7-7 ', ' 41-1-6\n']], [['01-01-2', '01-05-1'], ['\t01-12-7\n', ' 41-1-6\n', ' 41-7-7 ']]], ['generated mix 41', [[' 2-12-1 ', '40-7-1\n', '\t03-1-2\n', '\t40-1-6\n', '01-7-6', '\t1-7-0\n']], [['01-07-6', '02-12-1', '03-01-2', '40-07-1', '40-01-6'], ['\t1-7-0\n']]]], [['generated mix 41', [[' 2-12-1 ', '40-7-1\n', '\t03-1-2\n', '\t40-1-6\n', '01-7-6', '\t1-7-0\n']], [['01-07-6', '02-12-1', '03-01-2', '40-07-1', '40-01-6'], ['\t1-7-0\n']]], ['generated mix 42', [['40-12-0\n', 'X 40-12-7', '\t02-7-2', ' 3-12-6\n', '40-05-2\n', ' 41-12-2 ', '0-7-2\n']], [['02-07-2', '03-12-6', '40-05-2'], [' 41-12-2 ', '0-7-2\n', '40-12-0\n', 'X 40-12-7']]], ['dup invalid kept', [['B', 'A', 'B']], [[], ['A', 'B', 'B']]], ['serpentine', [['2-01-1', '1-05-1', '2-09-1', '1-02-1']], [['01-02-1', '01-05-1', '02-09-1', '02-01-1'], []]], ['whitespace', [[' 1-1-1\n', '\t1-2-1']], [['01-01-1', '01-02-1'], []]], ['range limits', [['40-1-6', '41-1-1', '1-1-7', '0-1-1']], [['40-01-6'], ['0-1-1', '1-1-7', '41-1-1']]], ['generated mix 44', [['\t3 -12-2\n', ' 3-1-7', ' 40-7-6\n']], [['40-07-6'], ['\t3 -12-2\n', ' 3-1-7']]], ['generated mix 52', [['1-1-7', '1-05-6', '03-7-2', '\t1-12-2 ', 'X\t0-7-2 ', '40-1-7', '\t1 -05-1 ']], [['01-05-6', '01-12-2', '03-07-2'], ['\t1 -05-1 ', '1-1-7', '40-1-7', 'X\t0-7-2 ']]]]]
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
range limits[['00-01-1', '40-01-6'], ['1-1-7', '41-1-1']][['40-01-6'], ['0-1-1', '1-1-7', '41-1-1']]Failed
generated mix 3[['00-07-6'], ['\t0 -1-1 ', '\t1 -05-2\n', '40 -1-7']][[], ['\t0 -1-1 ', '\t1 -05-2\n', '0-7-6', '40 -1-7']]Failed
serpentine[['01-02-1', '01-05-1', '02-09-1', '02-01-1'], []][['01-02-1', '01-05-1', '02-09-1', '02-01-1'], []]Passed
whitespace[['01-01-1', '01-02-1'], []][['01-01-1', '01-02-1'], []]Passed
dup invalid kept[[], ['A', 'B', 'B']][[], ['A', 'B', 'B']]Passed
levels ascend[['03-04-1', '03-04-2'], []][['03-04-1', '03-04-2'], []]Passed
generated mix 7[['01-12-2', '03-07-2'], ['\t2-05-0', ' 01-05-7', '1-12-7 ', 'X 0-7-0', 'X 2-7-0 ']][['01-12-2', '03-07-2'], ['\t2-05-0', ' 01-05-7', '1-12-7 ', 'X 0-7-0', 'X 2-7-0 ']]Passed
generated mix 15[['02-07-1', '40-01-2'], ['\t41-12-2']][['02-07-1', '40-01-2'], ['\t41-12-2']]Passed

SHA-256 / 1f3915e449e80257a8fb34d56c973dd1fcf085ed29c9caf6727d47ac65b587a0

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Verification & scope

Stipulated code format and layout; no cross aisles or zone routing. 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 2026-09-29T14:52:11.838144+00:00.

Case digest / a45672351c3884c643d376ebb0f44ba539c493a231e22b7100e32eb6c6166a0c