FA-96211 / Postal address normalization / Open access
Block range side assignment: position measured from the lower bound · case 01
On a descending range the position is mirrored (near the start reads as near the end).
ROOT CAUSE
The offset is taken from min(from, to) instead of from the range start.
VERIFIED REPAIR
Measure (house - from) / (to - from) so direction is preserved.
Unsuccessful approach: Measuring from the start but dividing by the absolute span gives negative positions.
Case contract
Input [house, segment] where the segment maps "left"/"right" to [from, to] house ranges (either direction, both ends sharing parity). Check left, then right: a side matches when the house lies between the ends inclusive and has the parity of "from". Return [side, position] with position the reduced fraction (house - from) / (to - from) as a string, "0" for a single-address range, or None when no side matches.
Why this case matters
Assigning a normalized address to the correct block face and position drives geocoding and carrier walk order.
1 / The failure
Exit 1"""Failure Map reference implementation. Python standard library only."""
import json
from fractions import Fraction
N = 1
observations = []
def solve(x):
house, seg = x
for side in ('left', 'right'):
lo_hi = seg.get(side)
if not lo_hi:
continue
a, b = lo_hi
if min(a, b) <= house <= max(a, b) and house % 2 == a % 2:
if a == b:
return [side, '0']
return [side, str(Fraction(house - min(a, b), abs(b - a)))]
return None
def check(label, actual, expected):
observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[['odd house on odd left side', [103, {'left': [101, 199], 'right': [100, 198]}], ['left', '1/49']], ['even house on even right side', [152, {'left': [101, 199], 'right': [100, 198]}], ['right', '26/49']], ['range end is inclusive', [199, {'left': [101, 199], 'right': [100, 198]}], ['left', '1']], ['descending range', [296, {'left': [298, 200], 'right': [299, 201]}], ['left', '1/49']], ['single-address range', [17, {'left': [17, 17], 'right': [16, 16]}], ['left', '0']], ['conflicting sides resolve to left', [5, {'right': [1, 9], 'left': [1, 9]}], ['left', '1/2']], ['even left side', [122, {'left': [100, 198], 'right': [101, 199]}], ['left', '11/49']], ['outside both ranges', [501, {'left': [101, 199], 'right': [100, 198]}], None]], [['odd house on odd left side', [105, {'left': [101, 199], 'right': [100, 198]}], ['left', '2/49']], ['even house on even right side', [154, {'left': [101, 199], 'right': [100, 198]}], ['right', '27/49']], ['range end is inclusive', [199, {'left': [101, 199], 'right': [100, 198]}], ['left', '1']], ['descending range', [294, {'left': [298, 200], 'right': [299, 201]}], ['left', '2/49']], ['single-address range', [19, {'left': [19, 19], 'right': [16, 16]}], ['left', '0']], ['conflicting sides resolve to left', [5, {'right': [1, 9], 'left': [1, 9]}], ['left', '1/2']], ['even left side', [124, {'left': [100, 198], 'right': [101, 199]}], ['left', '12/49']], ['outside both ranges', [502, {'left': [101, 199], 'right': [100, 198]}], None]], [['odd house on odd left side', [107, {'left': [101, 199], 'right': [100, 198]}], ['left', '3/49']], ['even house on even right side', [156, {'left': [101, 199], 'right': [100, 198]}], ['right', '4/7']], ['range end is inclusive', [199, {'left': [101, 199], 'right': [100, 198]}], ['left', '1']], ['descending range', [292, {'left': [298, 200], 'right': [299, 201]}], ['left', '3/49']], ['single-address range', [21, {'left': [21, 21], 'right': [16, 16]}], ['left', '0']], ['conflicting sides resolve to left', [5, {'right': [1, 9], 'left': [1, 9]}], ['left', '1/2']], ['even left side', [126, {'left': [100, 198], 'right': [101, 199]}], ['left', '13/49']], ['outside both ranges', [503, {'left': [101, 199], 'right': [100, 198]}], None]], [['odd house on odd left side', [109, {'left': [101, 199], 'right': [100, 198]}], ['left', '4/49']], ['even house on even right side', [158, {'left': [101, 199], 'right': [100, 198]}], ['right', '29/49']], ['range end is inclusive', [199, {'left': [101, 199], 'right': [100, 198]}], ['left', '1']], ['descending range', [290, {'left': [298, 200], 'right': [299, 201]}], ['left', '4/49']], ['single-address range', [23, {'left': [23, 23], 'right': [16, 16]}], ['left', '0']], ['conflicting sides resolve to left', [5, {'right': [1, 9], 'left': [1, 9]}], ['left', '1/2']], ['even left side', [128, {'left': [100, 198], 'right': [101, 199]}], ['left', '2/7']], ['outside both ranges', [504, {'left': [101, 199], 'right': [100, 198]}], None]], [['odd house on odd left side', [111, {'left': [101, 199], 'right': [100, 198]}], ['left', '5/49']], ['even house on even right side', [160, {'left': [101, 199], 'right': [100, 198]}], ['right', '30/49']], ['range end is inclusive', [199, {'left': [101, 199], 'right': [100, 198]}], ['left', '1']], ['descending range', [288, {'left': [298, 200], 'right': [299, 201]}], ['left', '5/49']], ['single-address range', [25, {'left': [25, 25], 'right': [16, 16]}], ['left', '0']], ['conflicting sides resolve to left', [5, {'right': [1, 9], 'left': [1, 9]}], ['left', '1/2']], ['even left side', [130, {'left': [100, 198], 'right': [101, 199]}], ['left', '15/49']], ['outside both ranges', [505, {'left': [101, 199], 'right': [100, 198]}], None]]]
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 fixture | Actual | Expected | Outcome |
|---|---|---|---|
| odd house on odd left side | ['left', '1/49'] | ['left', '1/49'] | Passed |
| even house on even right side | ['right', '26/49'] | ['right', '26/49'] | Passed |
| range end is inclusive | ['left', '1'] | ['left', '1'] | Passed |
| descending range | ['left', '48/49'] | ['left', '1/49'] | Failed |
| single-address range | ['left', '0'] | ['left', '0'] | Passed |
| conflicting sides resolve to left | ['left', '1/2'] | ['left', '1/2'] | Passed |
| even left side | ['left', '11/49'] | ['left', '11/49'] | Passed |
| outside both ranges | None | None | Passed |
SHA-256 / d7c142511e02e4df8de6810351ad6bcac5cc0be1349d41ad726e0894000d60eb
2 / The unsuccessful fix
Exit 1"""Failure Map reference implementation. Python standard library only."""
import json
from fractions import Fraction
N = 1
observations = []
def solve(x):
house, seg = x
for side in ('left', 'right'):
lo_hi = seg.get(side)
if not lo_hi:
continue
a, b = lo_hi
if min(a, b) <= house <= max(a, b) and house % 2 == a % 2:
if a == b:
return [side, '0']
return [side, str(Fraction(house - a, abs(b - a)))]
return None
def check(label, actual, expected):
observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[['odd house on odd left side', [103, {'left': [101, 199], 'right': [100, 198]}], ['left', '1/49']], ['even house on even right side', [152, {'left': [101, 199], 'right': [100, 198]}], ['right', '26/49']], ['range end is inclusive', [199, {'left': [101, 199], 'right': [100, 198]}], ['left', '1']], ['descending range', [296, {'left': [298, 200], 'right': [299, 201]}], ['left', '1/49']], ['single-address range', [17, {'left': [17, 17], 'right': [16, 16]}], ['left', '0']], ['conflicting sides resolve to left', [5, {'right': [1, 9], 'left': [1, 9]}], ['left', '1/2']], ['even left side', [122, {'left': [100, 198], 'right': [101, 199]}], ['left', '11/49']], ['outside both ranges', [501, {'left': [101, 199], 'right': [100, 198]}], None]], [['odd house on odd left side', [105, {'left': [101, 199], 'right': [100, 198]}], ['left', '2/49']], ['even house on even right side', [154, {'left': [101, 199], 'right': [100, 198]}], ['right', '27/49']], ['range end is inclusive', [199, {'left': [101, 199], 'right': [100, 198]}], ['left', '1']], ['descending range', [294, {'left': [298, 200], 'right': [299, 201]}], ['left', '2/49']], ['single-address range', [19, {'left': [19, 19], 'right': [16, 16]}], ['left', '0']], ['conflicting sides resolve to left', [5, {'right': [1, 9], 'left': [1, 9]}], ['left', '1/2']], ['even left side', [124, {'left': [100, 198], 'right': [101, 199]}], ['left', '12/49']], ['outside both ranges', [502, {'left': [101, 199], 'right': [100, 198]}], None]], [['odd house on odd left side', [107, {'left': [101, 199], 'right': [100, 198]}], ['left', '3/49']], ['even house on even right side', [156, {'left': [101, 199], 'right': [100, 198]}], ['right', '4/7']], ['range end is inclusive', [199, {'left': [101, 199], 'right': [100, 198]}], ['left', '1']], ['descending range', [292, {'left': [298, 200], 'right': [299, 201]}], ['left', '3/49']], ['single-address range', [21, {'left': [21, 21], 'right': [16, 16]}], ['left', '0']], ['conflicting sides resolve to left', [5, {'right': [1, 9], 'left': [1, 9]}], ['left', '1/2']], ['even left side', [126, {'left': [100, 198], 'right': [101, 199]}], ['left', '13/49']], ['outside both ranges', [503, {'left': [101, 199], 'right': [100, 198]}], None]], [['odd house on odd left side', [109, {'left': [101, 199], 'right': [100, 198]}], ['left', '4/49']], ['even house on even right side', [158, {'left': [101, 199], 'right': [100, 198]}], ['right', '29/49']], ['range end is inclusive', [199, {'left': [101, 199], 'right': [100, 198]}], ['left', '1']], ['descending range', [290, {'left': [298, 200], 'right': [299, 201]}], ['left', '4/49']], ['single-address range', [23, {'left': [23, 23], 'right': [16, 16]}], ['left', '0']], ['conflicting sides resolve to left', [5, {'right': [1, 9], 'left': [1, 9]}], ['left', '1/2']], ['even left side', [128, {'left': [100, 198], 'right': [101, 199]}], ['left', '2/7']], ['outside both ranges', [504, {'left': [101, 199], 'right': [100, 198]}], None]], [['odd house on odd left side', [111, {'left': [101, 199], 'right': [100, 198]}], ['left', '5/49']], ['even house on even right side', [160, {'left': [101, 199], 'right': [100, 198]}], ['right', '30/49']], ['range end is inclusive', [199, {'left': [101, 199], 'right': [100, 198]}], ['left', '1']], ['descending range', [288, {'left': [298, 200], 'right': [299, 201]}], ['left', '5/49']], ['single-address range', [25, {'left': [25, 25], 'right': [16, 16]}], ['left', '0']], ['conflicting sides resolve to left', [5, {'right': [1, 9], 'left': [1, 9]}], ['left', '1/2']], ['even left side', [130, {'left': [100, 198], 'right': [101, 199]}], ['left', '15/49']], ['outside both ranges', [505, {'left': [101, 199], 'right': [100, 198]}], None]]]
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 fixture | Actual | Expected | Outcome |
|---|---|---|---|
| odd house on odd left side | ['left', '1/49'] | ['left', '1/49'] | Passed |
| even house on even right side | ['right', '26/49'] | ['right', '26/49'] | Passed |
| range end is inclusive | ['left', '1'] | ['left', '1'] | Passed |
| descending range | ['left', '-1/49'] | ['left', '1/49'] | Failed |
| single-address range | ['left', '0'] | ['left', '0'] | Passed |
| conflicting sides resolve to left | ['left', '1/2'] | ['left', '1/2'] | Passed |
| even left side | ['left', '11/49'] | ['left', '11/49'] | Passed |
| outside both ranges | None | None | Passed |
SHA-256 / e4cc2f339953ddef806e208ccd75c680faed5928de495989c61d7f88c4106734
3 / The verified repair
Exit 0"""Failure Map reference implementation. Python standard library only."""
import json
from fractions import Fraction
N = 1
observations = []
def solve(x):
house, seg = x
for side in ('left', 'right'):
lo_hi = seg.get(side)
if not lo_hi:
continue
a, b = lo_hi
if min(a, b) <= house <= max(a, b) and house % 2 == a % 2:
if a == b:
return [side, '0']
return [side, str(Fraction(house - a, b - a))]
return None
def check(label, actual, expected):
observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[['odd house on odd left side', [103, {'left': [101, 199], 'right': [100, 198]}], ['left', '1/49']], ['even house on even right side', [152, {'left': [101, 199], 'right': [100, 198]}], ['right', '26/49']], ['range end is inclusive', [199, {'left': [101, 199], 'right': [100, 198]}], ['left', '1']], ['descending range', [296, {'left': [298, 200], 'right': [299, 201]}], ['left', '1/49']], ['single-address range', [17, {'left': [17, 17], 'right': [16, 16]}], ['left', '0']], ['conflicting sides resolve to left', [5, {'right': [1, 9], 'left': [1, 9]}], ['left', '1/2']], ['even left side', [122, {'left': [100, 198], 'right': [101, 199]}], ['left', '11/49']], ['outside both ranges', [501, {'left': [101, 199], 'right': [100, 198]}], None]], [['odd house on odd left side', [105, {'left': [101, 199], 'right': [100, 198]}], ['left', '2/49']], ['even house on even right side', [154, {'left': [101, 199], 'right': [100, 198]}], ['right', '27/49']], ['range end is inclusive', [199, {'left': [101, 199], 'right': [100, 198]}], ['left', '1']], ['descending range', [294, {'left': [298, 200], 'right': [299, 201]}], ['left', '2/49']], ['single-address range', [19, {'left': [19, 19], 'right': [16, 16]}], ['left', '0']], ['conflicting sides resolve to left', [5, {'right': [1, 9], 'left': [1, 9]}], ['left', '1/2']], ['even left side', [124, {'left': [100, 198], 'right': [101, 199]}], ['left', '12/49']], ['outside both ranges', [502, {'left': [101, 199], 'right': [100, 198]}], None]], [['odd house on odd left side', [107, {'left': [101, 199], 'right': [100, 198]}], ['left', '3/49']], ['even house on even right side', [156, {'left': [101, 199], 'right': [100, 198]}], ['right', '4/7']], ['range end is inclusive', [199, {'left': [101, 199], 'right': [100, 198]}], ['left', '1']], ['descending range', [292, {'left': [298, 200], 'right': [299, 201]}], ['left', '3/49']], ['single-address range', [21, {'left': [21, 21], 'right': [16, 16]}], ['left', '0']], ['conflicting sides resolve to left', [5, {'right': [1, 9], 'left': [1, 9]}], ['left', '1/2']], ['even left side', [126, {'left': [100, 198], 'right': [101, 199]}], ['left', '13/49']], ['outside both ranges', [503, {'left': [101, 199], 'right': [100, 198]}], None]], [['odd house on odd left side', [109, {'left': [101, 199], 'right': [100, 198]}], ['left', '4/49']], ['even house on even right side', [158, {'left': [101, 199], 'right': [100, 198]}], ['right', '29/49']], ['range end is inclusive', [199, {'left': [101, 199], 'right': [100, 198]}], ['left', '1']], ['descending range', [290, {'left': [298, 200], 'right': [299, 201]}], ['left', '4/49']], ['single-address range', [23, {'left': [23, 23], 'right': [16, 16]}], ['left', '0']], ['conflicting sides resolve to left', [5, {'right': [1, 9], 'left': [1, 9]}], ['left', '1/2']], ['even left side', [128, {'left': [100, 198], 'right': [101, 199]}], ['left', '2/7']], ['outside both ranges', [504, {'left': [101, 199], 'right': [100, 198]}], None]], [['odd house on odd left side', [111, {'left': [101, 199], 'right': [100, 198]}], ['left', '5/49']], ['even house on even right side', [160, {'left': [101, 199], 'right': [100, 198]}], ['right', '30/49']], ['range end is inclusive', [199, {'left': [101, 199], 'right': [100, 198]}], ['left', '1']], ['descending range', [288, {'left': [298, 200], 'right': [299, 201]}], ['left', '5/49']], ['single-address range', [25, {'left': [25, 25], 'right': [16, 16]}], ['left', '0']], ['conflicting sides resolve to left', [5, {'right': [1, 9], 'left': [1, 9]}], ['left', '1/2']], ['even left side', [130, {'left': [100, 198], 'right': [101, 199]}], ['left', '15/49']], ['outside both ranges', [505, {'left': [101, 199], 'right': [100, 198]}], None]]]
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 fixture | Actual | Expected | Outcome |
|---|---|---|---|
| odd house on odd left side | ['left', '1/49'] | ['left', '1/49'] | Passed |
| even house on even right side | ['right', '26/49'] | ['right', '26/49'] | Passed |
| range end is inclusive | ['left', '1'] | ['left', '1'] | Passed |
| descending range | ['left', '1/49'] | ['left', '1/49'] | Passed |
| single-address range | ['left', '0'] | ['left', '0'] | Passed |
| conflicting sides resolve to left | ['left', '1/2'] | ['left', '1/2'] | Passed |
| even left side | ['left', '11/49'] | ['left', '11/49'] | Passed |
| outside both ranges | None | None | Passed |
SHA-256 / c89a7ee23cf20a0eb58c6d40c40f23df4bafe8fb429196f33208107e1b323637
Verification & scope
A deterministic toy contract over synthetic, obviously fictitious addresses. The rules are stipulated for this model only and make no claim of conformance with any postal authority 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 2026-09-29T14:52:20.691609+00:00.
Case digest / 2a2cfc528c770e7a08a095eb3a3015487db7a44bddc44ad9b052b4e1a86e35fb