FA-83326 / Go territory scoring / Open access
Stones one line beyond the board are accepted · case 01
A coordinate equal to size passes validation.
ROOT CAUSE
The upper bound is inclusive.
VERIFIED REPAIR
Require 0 <= coordinate < size.
Unsuccessful approach: Dropping the lower bound accepts negative coordinates.
Case contract
Input [size, count, stones]. Check in order: every stone on the board ("range"), no duplicate ("duplicate"), exactly count stones and 2 <= count <= 9 ("count"). Otherwise "ok".
Why this case matters
Go servers and scoring tools compute this value automatically; a wrong answer changes a game result.
1 / The failure
Exit 1"""Failure Map reference implementation. Python standard library only."""
import json
N = 1
observations = []
def solve(x):
size, count, stones = x
seen = set()
for r, c in stones:
if not (0 <= r <= size and 0 <= c <= size):
return 'range'
for r, c in stones:
if (r, c) in seen:
return 'duplicate'
seen.add((r, c))
if len(stones) != count:
return 'count'
if count < 2 or count > 9:
return 'count'
return 'ok'
def check(label, actual, expected):
observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[[[13, 1, [[6, 7]]], 'count'], [[19, 6, [[11, 2], [8, 5], [4, 4], [13, 0], [13, 0], [18, 7], [16, 11]]], 'duplicate'], [[13, 10, [[2, 5], [11, 3], [10, 11], [11, 4], [8, 9], [8, 12], [12, 10], [10, 2], [5, 4], [9, 5], [2, 5]]], 'duplicate'], [[9, 7, [[6, 0], [6, 0], [8, 5], [0, 0], [6, 3], [0, 5], [1, 3]]], 'duplicate'], [[9, 5, [[-1, 7], [0, 2], [8, 4], [4, 1]]], 'range'], [[13, 6, [[3, 6], [11, 11], [4, 13], [9, 0], [1, 1], [12, 9], [3, 6]]], 'range'], [[9, 3, [[8, 1], [5, 2], [6, 2], [7, 2], [8, 1]]], 'duplicate'], [[13, 5, [[2, 1], [6, 10], [6, 4], [2, 0], [0, -1]]], 'range']], [[[19, 4, [[7, 1], [8, 9], [14, 2], [11, 12], [7, 1]]], 'duplicate'], [[19, 1, [[16, 11]]], 'count'], [[9, 4, [[6, 3], [1, 8], [0, 0], [6, 3]]], 'duplicate'], [[13, 6, [[0, 10], [10, 12], [0, 10], [12, 10], [9, 2], [6, 8]]], 'duplicate'], [[19, 8, [[12, 5], [16, 15], [17, 16], [10, 3], [0, 13], [14, 9], [7, 1], [9, 11]]], 'ok'], [[9, 6, [[3, 5], [1, 3], [5, 6], [2, 2], [0, 4], [8, 1], [1, 7]]], 'count'], [[13, 5, [[2, 1], [6, 10], [6, 4], [2, 0], [0, -1]]], 'range'], [[9, 9, [[1, 3], [7, 2], [3, 2], [4, 7], [4, 9], [1, 4], [1, 6], [7, 7], [6, 5], [1, 3]]], 'range']], [[[13, 6, [[11, 11], [5, 6], [8, 12], [8, 0], [10, 6], [1, 9], [2, 8]]], 'count'], [[13, 4, [[6, 3], [6, 5], [6, 11]]], 'count'], [[9, 10, [[5, 7], [1, 6], [6, 6], [4, 3], [4, 6], [5, 8], [7, 5], [5, 0], [5, 3], [5, 7]]], 'duplicate'], [[9, 5, [[3, 6], [8, 4], [0, 2], [7, 8], [1, 7]]], 'ok'], [[9, 1, [[1, 5], [7, 2]]], 'count'], [[13, 3, [[10, 0], [0, 11]]], 'count'], [[13, 5, [[2, 1], [6, 10], [6, 4], [2, 0], [0, -1]]], 'range'], [[9, 2, [[9, 0], [1, 1]]], 'range']], [[[13, 3, [[5, 9], [5, 9], [2, 6]]], 'duplicate'], [[13, 2, [[1, 3], [12, 8]]], 'ok'], [[19, 4, [[4, 4], [6, 18], [15, 18], [12, 5]]], 'ok'], [[13, 0, []], 'count'], [[19, 5, [[7, 1], [7, 3], [13, 10], [3, 11], [3, 8]]], 'ok'], [[19, 7, [[8, 18], [18, 18], [12, 4], [10, 13], [16, 1], [8, 1], [14, 7], [8, 18]]], 'duplicate'], [[13, 5, [[2, 1], [6, 10], [6, 4], [2, 0], [0, -1]]], 'range'], [[13, 8, [[13, 1], [4, 11], [9, 6], [0, 11], [7, 10], [4, 3], [2, 9], [7, 1], [13, 1]]], 'range']], [[[13, 10, [[11, 9], [11, 11], [7, 2], [0, 2], [10, 3], [11, 5], [7, 6], [1, 10], [3, 2], [3, 12]]], 'count'], [[13, 4, [[6, 0], [7, 9], [12, 11], [11, 9], [12, 5]]], 'count'], [[19, 1, [[10, 17], [11, 15]]], 'count'], [[13, 8, [[12, 0], [8, 0], [9, 8], [8, 5], [2, 3], [5, 12], [7, 5], [5, 0]]], 'ok'], [[13, 4, [[3, 7], [1, 12], [0, 11], [4, 6]]], 'ok'], [[13, 2, [[0, 10], [1, 4], [0, 10]]], 'duplicate'], [[13, 5, [[2, 1], [6, 10], [6, 4], [2, 0], [0, -1]]], 'range'], [[9, 2, [[0, 9], [1, 1]]], 'range']]]
for i, (args, expected) in enumerate(fixtures[N-1]):
check("free placement case %d" % i, 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 fixture | Actual | Expected | Outcome |
|---|---|---|---|
| free placement case 0 | count | count | Passed |
| free placement case 1 | duplicate | duplicate | Passed |
| free placement case 2 | duplicate | duplicate | Passed |
| free placement case 3 | duplicate | duplicate | Passed |
| free placement case 4 | range | range | Passed |
| free placement case 5 | duplicate | range | Failed |
| free placement case 6 | duplicate | duplicate | Passed |
| free placement case 7 | range | range | Passed |
SHA-256 / 1b1c7aaad628a06316ad3cec1a1cd14cf182f5ba853ed9ef134a2e88c551d64d
2 / The unsuccessful fix
Exit 1"""Failure Map reference implementation. Python standard library only."""
import json
N = 1
observations = []
def solve(x):
size, count, stones = x
seen = set()
for r, c in stones:
if not (r < size and c < size):
return 'range'
for r, c in stones:
if (r, c) in seen:
return 'duplicate'
seen.add((r, c))
if len(stones) != count:
return 'count'
if count < 2 or count > 9:
return 'count'
return 'ok'
def check(label, actual, expected):
observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[[[13, 1, [[6, 7]]], 'count'], [[19, 6, [[11, 2], [8, 5], [4, 4], [13, 0], [13, 0], [18, 7], [16, 11]]], 'duplicate'], [[13, 10, [[2, 5], [11, 3], [10, 11], [11, 4], [8, 9], [8, 12], [12, 10], [10, 2], [5, 4], [9, 5], [2, 5]]], 'duplicate'], [[9, 7, [[6, 0], [6, 0], [8, 5], [0, 0], [6, 3], [0, 5], [1, 3]]], 'duplicate'], [[9, 5, [[-1, 7], [0, 2], [8, 4], [4, 1]]], 'range'], [[13, 6, [[3, 6], [11, 11], [4, 13], [9, 0], [1, 1], [12, 9], [3, 6]]], 'range'], [[9, 3, [[8, 1], [5, 2], [6, 2], [7, 2], [8, 1]]], 'duplicate'], [[13, 5, [[2, 1], [6, 10], [6, 4], [2, 0], [0, -1]]], 'range']], [[[19, 4, [[7, 1], [8, 9], [14, 2], [11, 12], [7, 1]]], 'duplicate'], [[19, 1, [[16, 11]]], 'count'], [[9, 4, [[6, 3], [1, 8], [0, 0], [6, 3]]], 'duplicate'], [[13, 6, [[0, 10], [10, 12], [0, 10], [12, 10], [9, 2], [6, 8]]], 'duplicate'], [[19, 8, [[12, 5], [16, 15], [17, 16], [10, 3], [0, 13], [14, 9], [7, 1], [9, 11]]], 'ok'], [[9, 6, [[3, 5], [1, 3], [5, 6], [2, 2], [0, 4], [8, 1], [1, 7]]], 'count'], [[13, 5, [[2, 1], [6, 10], [6, 4], [2, 0], [0, -1]]], 'range'], [[9, 9, [[1, 3], [7, 2], [3, 2], [4, 7], [4, 9], [1, 4], [1, 6], [7, 7], [6, 5], [1, 3]]], 'range']], [[[13, 6, [[11, 11], [5, 6], [8, 12], [8, 0], [10, 6], [1, 9], [2, 8]]], 'count'], [[13, 4, [[6, 3], [6, 5], [6, 11]]], 'count'], [[9, 10, [[5, 7], [1, 6], [6, 6], [4, 3], [4, 6], [5, 8], [7, 5], [5, 0], [5, 3], [5, 7]]], 'duplicate'], [[9, 5, [[3, 6], [8, 4], [0, 2], [7, 8], [1, 7]]], 'ok'], [[9, 1, [[1, 5], [7, 2]]], 'count'], [[13, 3, [[10, 0], [0, 11]]], 'count'], [[13, 5, [[2, 1], [6, 10], [6, 4], [2, 0], [0, -1]]], 'range'], [[9, 2, [[9, 0], [1, 1]]], 'range']], [[[13, 3, [[5, 9], [5, 9], [2, 6]]], 'duplicate'], [[13, 2, [[1, 3], [12, 8]]], 'ok'], [[19, 4, [[4, 4], [6, 18], [15, 18], [12, 5]]], 'ok'], [[13, 0, []], 'count'], [[19, 5, [[7, 1], [7, 3], [13, 10], [3, 11], [3, 8]]], 'ok'], [[19, 7, [[8, 18], [18, 18], [12, 4], [10, 13], [16, 1], [8, 1], [14, 7], [8, 18]]], 'duplicate'], [[13, 5, [[2, 1], [6, 10], [6, 4], [2, 0], [0, -1]]], 'range'], [[13, 8, [[13, 1], [4, 11], [9, 6], [0, 11], [7, 10], [4, 3], [2, 9], [7, 1], [13, 1]]], 'range']], [[[13, 10, [[11, 9], [11, 11], [7, 2], [0, 2], [10, 3], [11, 5], [7, 6], [1, 10], [3, 2], [3, 12]]], 'count'], [[13, 4, [[6, 0], [7, 9], [12, 11], [11, 9], [12, 5]]], 'count'], [[19, 1, [[10, 17], [11, 15]]], 'count'], [[13, 8, [[12, 0], [8, 0], [9, 8], [8, 5], [2, 3], [5, 12], [7, 5], [5, 0]]], 'ok'], [[13, 4, [[3, 7], [1, 12], [0, 11], [4, 6]]], 'ok'], [[13, 2, [[0, 10], [1, 4], [0, 10]]], 'duplicate'], [[13, 5, [[2, 1], [6, 10], [6, 4], [2, 0], [0, -1]]], 'range'], [[9, 2, [[0, 9], [1, 1]]], 'range']]]
for i, (args, expected) in enumerate(fixtures[N-1]):
check("free placement case %d" % i, 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 fixture | Actual | Expected | Outcome |
|---|---|---|---|
| free placement case 0 | count | count | Passed |
| free placement case 1 | duplicate | duplicate | Passed |
| free placement case 2 | duplicate | duplicate | Passed |
| free placement case 3 | duplicate | duplicate | Passed |
| free placement case 4 | count | range | Failed |
| free placement case 5 | range | range | Passed |
| free placement case 6 | duplicate | duplicate | Passed |
| free placement case 7 | ok | range | Failed |
SHA-256 / 5afab53363e6112145d7e6dac8b82a6d1d6ee7360a5fc74c28d3feb444f741c5
3 / The verified repair
Exit 0"""Failure Map reference implementation. Python standard library only."""
import json
N = 1
observations = []
def solve(x):
size, count, stones = x
seen = set()
for r, c in stones:
if not (0 <= r < size and 0 <= c < size):
return 'range'
for r, c in stones:
if (r, c) in seen:
return 'duplicate'
seen.add((r, c))
if len(stones) != count:
return 'count'
if count < 2 or count > 9:
return 'count'
return 'ok'
def check(label, actual, expected):
observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[[[13, 1, [[6, 7]]], 'count'], [[19, 6, [[11, 2], [8, 5], [4, 4], [13, 0], [13, 0], [18, 7], [16, 11]]], 'duplicate'], [[13, 10, [[2, 5], [11, 3], [10, 11], [11, 4], [8, 9], [8, 12], [12, 10], [10, 2], [5, 4], [9, 5], [2, 5]]], 'duplicate'], [[9, 7, [[6, 0], [6, 0], [8, 5], [0, 0], [6, 3], [0, 5], [1, 3]]], 'duplicate'], [[9, 5, [[-1, 7], [0, 2], [8, 4], [4, 1]]], 'range'], [[13, 6, [[3, 6], [11, 11], [4, 13], [9, 0], [1, 1], [12, 9], [3, 6]]], 'range'], [[9, 3, [[8, 1], [5, 2], [6, 2], [7, 2], [8, 1]]], 'duplicate'], [[13, 5, [[2, 1], [6, 10], [6, 4], [2, 0], [0, -1]]], 'range']], [[[19, 4, [[7, 1], [8, 9], [14, 2], [11, 12], [7, 1]]], 'duplicate'], [[19, 1, [[16, 11]]], 'count'], [[9, 4, [[6, 3], [1, 8], [0, 0], [6, 3]]], 'duplicate'], [[13, 6, [[0, 10], [10, 12], [0, 10], [12, 10], [9, 2], [6, 8]]], 'duplicate'], [[19, 8, [[12, 5], [16, 15], [17, 16], [10, 3], [0, 13], [14, 9], [7, 1], [9, 11]]], 'ok'], [[9, 6, [[3, 5], [1, 3], [5, 6], [2, 2], [0, 4], [8, 1], [1, 7]]], 'count'], [[13, 5, [[2, 1], [6, 10], [6, 4], [2, 0], [0, -1]]], 'range'], [[9, 9, [[1, 3], [7, 2], [3, 2], [4, 7], [4, 9], [1, 4], [1, 6], [7, 7], [6, 5], [1, 3]]], 'range']], [[[13, 6, [[11, 11], [5, 6], [8, 12], [8, 0], [10, 6], [1, 9], [2, 8]]], 'count'], [[13, 4, [[6, 3], [6, 5], [6, 11]]], 'count'], [[9, 10, [[5, 7], [1, 6], [6, 6], [4, 3], [4, 6], [5, 8], [7, 5], [5, 0], [5, 3], [5, 7]]], 'duplicate'], [[9, 5, [[3, 6], [8, 4], [0, 2], [7, 8], [1, 7]]], 'ok'], [[9, 1, [[1, 5], [7, 2]]], 'count'], [[13, 3, [[10, 0], [0, 11]]], 'count'], [[13, 5, [[2, 1], [6, 10], [6, 4], [2, 0], [0, -1]]], 'range'], [[9, 2, [[9, 0], [1, 1]]], 'range']], [[[13, 3, [[5, 9], [5, 9], [2, 6]]], 'duplicate'], [[13, 2, [[1, 3], [12, 8]]], 'ok'], [[19, 4, [[4, 4], [6, 18], [15, 18], [12, 5]]], 'ok'], [[13, 0, []], 'count'], [[19, 5, [[7, 1], [7, 3], [13, 10], [3, 11], [3, 8]]], 'ok'], [[19, 7, [[8, 18], [18, 18], [12, 4], [10, 13], [16, 1], [8, 1], [14, 7], [8, 18]]], 'duplicate'], [[13, 5, [[2, 1], [6, 10], [6, 4], [2, 0], [0, -1]]], 'range'], [[13, 8, [[13, 1], [4, 11], [9, 6], [0, 11], [7, 10], [4, 3], [2, 9], [7, 1], [13, 1]]], 'range']], [[[13, 10, [[11, 9], [11, 11], [7, 2], [0, 2], [10, 3], [11, 5], [7, 6], [1, 10], [3, 2], [3, 12]]], 'count'], [[13, 4, [[6, 0], [7, 9], [12, 11], [11, 9], [12, 5]]], 'count'], [[19, 1, [[10, 17], [11, 15]]], 'count'], [[13, 8, [[12, 0], [8, 0], [9, 8], [8, 5], [2, 3], [5, 12], [7, 5], [5, 0]]], 'ok'], [[13, 4, [[3, 7], [1, 12], [0, 11], [4, 6]]], 'ok'], [[13, 2, [[0, 10], [1, 4], [0, 10]]], 'duplicate'], [[13, 5, [[2, 1], [6, 10], [6, 4], [2, 0], [0, -1]]], 'range'], [[9, 2, [[0, 9], [1, 1]]], 'range']]]
for i, (args, expected) in enumerate(fixtures[N-1]):
check("free placement case %d" % i, 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 fixture | Actual | Expected | Outcome |
|---|---|---|---|
| free placement case 0 | count | count | Passed |
| free placement case 1 | duplicate | duplicate | Passed |
| free placement case 2 | duplicate | duplicate | Passed |
| free placement case 3 | duplicate | duplicate | Passed |
| free placement case 4 | range | range | Passed |
| free placement case 5 | range | range | Passed |
| free placement case 6 | duplicate | duplicate | Passed |
| free placement case 7 | range | range | Passed |
SHA-256 / c07a3dc5cd40c31717d7a0026e57c099a7ac0e8fb9f43cd9b9892a7dbd225826
Verification & scope
Small rectangular toy boards given as strings of B, W and dot; a bounded teaching model of one scoring or bookkeeping rule, not a complete rules engine or server implementation. 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 2026-09-29T14:50:20.646727+00:00.
Case digest / f91d409c5564136c4480b6487cfd60d68fa8321f5380d9897ea9f923a005e909