FAILURE MAP
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FA-96736 / Phone number formatting / Open access

Number list range compression: runs join numbers of different lengths · case 01

"98, 99, 100, 101" becomes one run "98-101".

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

ROOT CAUSE

Runs are extended on numeric succession alone.

THE FAILURE

Runs are extended on numeric succession alone.

Unsuccessful approach: Requiring the same first digit splits valid runs such as 1998-2000.

Case contract

Input a list of digit strings. Deduplicate and sort by (length, text). Consecutive numbers of equal length (each one greater than the previous) form a run. A run of one is emitted as is; a longer run is emitted as START-TAIL where TAIL is END without the prefix it shares with START.

Why this case matters

Number inventories are displayed and exported as compressed ranges; a wrong run boundary or tail misstates which numbers are owned.

1 / The failure

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

N = 1
observations = []
def solve(x):
    nums = sorted(set(x), key=lambda v: (len(v), v))
    out = []
    i = 0
    while i < len(nums):
        j = i
        while j + 1 < len(nums) and int(nums[j + 1]) == int(nums[j]) + 1:
            j += 1
        a, b = nums[i], nums[j]
        if a == b:
            out.append(a)
        else:
            k = 0
            while a[k] == b[k]:
                k += 1
            out.append(a + '-' + b[k:])
        i = j + 1
    return out
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[['run and singleton', ['5550110', '5550111', '5550112', '5550160'], ['5550110-2', '5550160']], ['duplicates inside a run', ['5550115', '5550115', '5550116'], ['5550115-6']], ['unsorted input', ['5550112', '5550110', '5550111'], ['5550110-2']], ['run crossing a hundred', ['5550198', '5550199', '5550200', '5550201'], ['5550198-201']], ['different lengths do not join', ['98', '99', '100', '101'], ['98-9', '100-1']], ['run crossing a thousand', ['1998', '1999', '2000'], ['1998-2000']], ['shorter number sorts first', ['0050', '100'], ['100', '0050']], ['gap of two', ['5550130', '5550132'], ['5550130', '5550132']]], [['run and singleton', ['5550120', '5550121', '5550122', '5550170'], ['5550120-2', '5550170']], ['duplicates inside a run', ['5550125', '5550125', '5550126'], ['5550125-6']], ['unsorted input', ['5550122', '5550120', '5550121'], ['5550120-2']], ['run crossing a hundred', ['5550198', '5550199', '5550200', '5550201'], ['5550198-201']], ['different lengths do not join', ['98', '99', '100', '101'], ['98-9', '100-1']], ['run crossing a thousand', ['1998', '1999', '2000'], ['1998-2000']], ['shorter number sorts first', ['0050', '100'], ['100', '0050']], ['gap of two', ['5550140', '5550142'], ['5550140', '5550142']]], [['run and singleton', ['5550130', '5550131', '5550132', '5550180'], ['5550130-2', '5550180']], ['duplicates inside a run', ['5550135', '5550135', '5550136'], ['5550135-6']], ['unsorted input', ['5550132', '5550130', '5550131'], ['5550130-2']], ['run crossing a hundred', ['5550198', '5550199', '5550200', '5550201'], ['5550198-201']], ['different lengths do not join', ['98', '99', '100', '101'], ['98-9', '100-1']], ['run crossing a thousand', ['1998', '1999', '2000'], ['1998-2000']], ['shorter number sorts first', ['0050', '100'], ['100', '0050']], ['gap of two', ['5550150', '5550152'], ['5550150', '5550152']]], [['run and singleton', ['5550140', '5550141', '5550142', '5550190'], ['5550140-2', '5550190']], ['duplicates inside a run', ['5550145', '5550145', '5550146'], ['5550145-6']], ['unsorted input', ['5550142', '5550140', '5550141'], ['5550140-2']], ['run crossing a hundred', ['5550198', '5550199', '5550200', '5550201'], ['5550198-201']], ['different lengths do not join', ['98', '99', '100', '101'], ['98-9', '100-1']], ['run crossing a thousand', ['1998', '1999', '2000'], ['1998-2000']], ['shorter number sorts first', ['0050', '100'], ['100', '0050']], ['gap of two', ['5550160', '5550162'], ['5550160', '5550162']]], [['run and singleton', ['5550150', '5550151', '5550152', '5550200'], ['5550150-2', '5550200']], ['duplicates inside a run', ['5550155', '5550155', '5550156'], ['5550155-6']], ['unsorted input', ['5550152', '5550150', '5550151'], ['5550150-2']], ['run crossing a hundred', ['5550198', '5550199', '5550200', '5550201'], ['5550198-201']], ['different lengths do not join', ['98', '99', '100', '101'], ['98-9', '100-1']], ['run crossing a thousand', ['1998', '1999', '2000'], ['1998-2000']], ['shorter number sorts first', ['0050', '100'], ['100', '0050']], ['gap of two', ['5550170', '5550172'], ['5550170', '5550172']]]]
for label, arg, expected in fixtures[N - 1]:
    check(label, solve(arg), 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
run and singleton['5550110-2', '5550160']['5550110-2', '5550160']Passed
duplicates inside a run['5550115-6']['5550115-6']Passed
unsorted input['5550110-2']['5550110-2']Passed
run crossing a hundred['5550198-201']['5550198-201']Passed
different lengths do not join['98-101']['98-9', '100-1']Failed
run crossing a thousand['1998-2000']['1998-2000']Passed
shorter number sorts first['100', '0050']['100', '0050']Passed
gap of two['5550130', '5550132']['5550130', '5550132']Passed

SHA-256 / acd4c8d458c42624239bbdb5218dd4c46b23f808b4d8a726ed37510ad5291038

2 / The unsuccessful fix

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

N = 1
observations = []
def solve(x):
    nums = sorted(set(x), key=lambda v: (len(v), v))
    out = []
    i = 0
    while i < len(nums):
        j = i
        while j + 1 < len(nums) and int(nums[j + 1]) == int(nums[j]) + 1 and nums[j + 1][0] == nums[i][0]:
            j += 1
        a, b = nums[i], nums[j]
        if a == b:
            out.append(a)
        else:
            k = 0
            while a[k] == b[k]:
                k += 1
            out.append(a + '-' + b[k:])
        i = j + 1
    return out
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[['run and singleton', ['5550110', '5550111', '5550112', '5550160'], ['5550110-2', '5550160']], ['duplicates inside a run', ['5550115', '5550115', '5550116'], ['5550115-6']], ['unsorted input', ['5550112', '5550110', '5550111'], ['5550110-2']], ['run crossing a hundred', ['5550198', '5550199', '5550200', '5550201'], ['5550198-201']], ['different lengths do not join', ['98', '99', '100', '101'], ['98-9', '100-1']], ['run crossing a thousand', ['1998', '1999', '2000'], ['1998-2000']], ['shorter number sorts first', ['0050', '100'], ['100', '0050']], ['gap of two', ['5550130', '5550132'], ['5550130', '5550132']]], [['run and singleton', ['5550120', '5550121', '5550122', '5550170'], ['5550120-2', '5550170']], ['duplicates inside a run', ['5550125', '5550125', '5550126'], ['5550125-6']], ['unsorted input', ['5550122', '5550120', '5550121'], ['5550120-2']], ['run crossing a hundred', ['5550198', '5550199', '5550200', '5550201'], ['5550198-201']], ['different lengths do not join', ['98', '99', '100', '101'], ['98-9', '100-1']], ['run crossing a thousand', ['1998', '1999', '2000'], ['1998-2000']], ['shorter number sorts first', ['0050', '100'], ['100', '0050']], ['gap of two', ['5550140', '5550142'], ['5550140', '5550142']]], [['run and singleton', ['5550130', '5550131', '5550132', '5550180'], ['5550130-2', '5550180']], ['duplicates inside a run', ['5550135', '5550135', '5550136'], ['5550135-6']], ['unsorted input', ['5550132', '5550130', '5550131'], ['5550130-2']], ['run crossing a hundred', ['5550198', '5550199', '5550200', '5550201'], ['5550198-201']], ['different lengths do not join', ['98', '99', '100', '101'], ['98-9', '100-1']], ['run crossing a thousand', ['1998', '1999', '2000'], ['1998-2000']], ['shorter number sorts first', ['0050', '100'], ['100', '0050']], ['gap of two', ['5550150', '5550152'], ['5550150', '5550152']]], [['run and singleton', ['5550140', '5550141', '5550142', '5550190'], ['5550140-2', '5550190']], ['duplicates inside a run', ['5550145', '5550145', '5550146'], ['5550145-6']], ['unsorted input', ['5550142', '5550140', '5550141'], ['5550140-2']], ['run crossing a hundred', ['5550198', '5550199', '5550200', '5550201'], ['5550198-201']], ['different lengths do not join', ['98', '99', '100', '101'], ['98-9', '100-1']], ['run crossing a thousand', ['1998', '1999', '2000'], ['1998-2000']], ['shorter number sorts first', ['0050', '100'], ['100', '0050']], ['gap of two', ['5550160', '5550162'], ['5550160', '5550162']]], [['run and singleton', ['5550150', '5550151', '5550152', '5550200'], ['5550150-2', '5550200']], ['duplicates inside a run', ['5550155', '5550155', '5550156'], ['5550155-6']], ['unsorted input', ['5550152', '5550150', '5550151'], ['5550150-2']], ['run crossing a hundred', ['5550198', '5550199', '5550200', '5550201'], ['5550198-201']], ['different lengths do not join', ['98', '99', '100', '101'], ['98-9', '100-1']], ['run crossing a thousand', ['1998', '1999', '2000'], ['1998-2000']], ['shorter number sorts first', ['0050', '100'], ['100', '0050']], ['gap of two', ['5550170', '5550172'], ['5550170', '5550172']]]]
for label, arg, expected in fixtures[N - 1]:
    check(label, solve(arg), 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
run and singleton['5550110-2', '5550160']['5550110-2', '5550160']Passed
duplicates inside a run['5550115-6']['5550115-6']Passed
unsorted input['5550110-2']['5550110-2']Passed
run crossing a hundred['5550198-201']['5550198-201']Passed
different lengths do not join['98-9', '100-1']['98-9', '100-1']Passed
run crossing a thousand['1998-9', '2000']['1998-2000']Failed
shorter number sorts first['100', '0050']['100', '0050']Passed
gap of two['5550130', '5550132']['5550130', '5550132']Passed

SHA-256 / 0967deacb1a7bacb99af4208f9fb222884cd8d2f893ea1b26ff2a91b79cbc55d

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.

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Verification & scope

A deterministic toy contract over synthetic, obviously fictitious telephone numbers and toy country tables. The rules are stipulated for this model only and make no claim of conformance with any numbering plan or telecommunications standard. 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 2026-09-29T14:52:25.575583+00:00.

Case digest / 3415c6e5b1c3d2b7b2c01cabc83a8ba3705216b694876efde01ef79b58bd28bf