FA-83141 / Go territory scoring / Open access

The chain grows through diagonal contacts · case 01

Clicking one group also marks a diagonally touching group.

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

ROOT CAUSE

Diagonal offsets are included in the chain expansion.

VERIFIED REPAIR

Grow chains through orthogonal same-colour neighbours only.

Unsuccessful approach: Adding only two diagonal directions still merges some separate groups.

Case contract

Input [board, dead_points, row, col]. Clicking a stone toggles its whole orthogonally connected chain: if the clicked stone is currently marked, unmark the chain, otherwise mark it. Clicking an empty point changes nothing. Return the sorted distinct dead points.

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):
    board, dead, r, c = x
    n = len(board)
    m = len(board[0])
    col = board[r][c]
    marked = {tuple(p) for p in dead}
    if col == '.':
        return sorted([list(p) for p in marked])
    chain = {(r, c)}
    stack = [(r, c)]
    while stack:
        i, j = stack.pop()
        for p, q in ((i + 1, j), (i, j + 1), (i - 1, j), (i, j - 1), (i + 1, j + 1), (i - 1, j - 1), (i + 1, j - 1), (i - 1, j + 1)):
            if 0 <= p < n and 0 <= q < m and board[p][q] == col and (p, q) not in chain:
                chain.add((p, q))
                stack.append((p, q))
    if (r, c) in marked:
        marked -= chain
    else:
        marked |= chain
    return sorted([list(p) for p in marked])
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[[[['.B.', 'B.B', '.B.'], [[1, 0], [1, 2]], 1, 2], [[1, 0]]], [[['.B.', 'B.B', '.B.'], [[1, 2], [0, 1], [1, 0]], 2, 1], [[0, 1], [1, 0], [1, 2], [2, 1]]], [[['B..W', 'B..W', 'B..W', 'B..W'], [[2, 3], [3, 0]], 3, 1], [[2, 3], [3, 0]]], [[['B..W', 'B..W', 'B..W', 'B..W'], [], 1, 1], []], [[['B..W', 'B..W', 'B..W', 'B..W'], [[0, 0]], 3, 0], [[0, 0], [1, 0], [2, 0], [3, 0]]], [[['.BW.', '.BW.', '.BW.', '.BW.'], [[0, 1], [0, 1], [2, 1], [0, 2]], 0, 1], [[0, 2]]], [[['.BW.', '.BW.', '.BW.', '.BW.'], [[0, 2]], 3, 2], [[0, 2], [1, 2], [2, 2], [3, 2]]], [[['..W.', '..W.', 'W..W'], [[0, 2], [2, 3], [0, 2]], 0, 2], [[2, 3]]]], [[[['.BW.', '.BW.', '.BW.', '.BW.'], [], 3, 1], [[0, 1], [1, 1], [2, 1], [3, 1]]], [[['..B..', '..B..', 'BBBBB', 'WWWWW', '..W..'], [[3, 3], [1, 2]], 3, 1], [[1, 2], [3, 0], [3, 1], [3, 2], [3, 3], [3, 4], [4, 2]]], [[['..B..', '..B..', 'BBBBB', 'WWWWW', '..W..'], [[4, 2], [4, 2], [1, 2], [0, 2]], 3, 2], [[0, 2], [1, 2], [3, 0], [3, 1], [3, 2], [3, 3], [3, 4], [4, 2]]], [[['..B..', '..B..', 'BBBBB', 'WWWWW', '..W..'], [], 3, 4], [[3, 0], [3, 1], [3, 2], [3, 3], [3, 4], [4, 2]]], [[['B.B.W', '.B.W.', 'B.BW.', 'BBW.W', '..W..'], [[2, 2]], 4, 0], [[2, 2]]], [[['B.B.W', '.B.W.', 'B.BW.', 'BBW.W', '..W..'], [[2, 3], [3, 0]], 2, 1], [[2, 3], [3, 0]]], [[['.B...', 'B....', '.....', '....W', '...W.'], [], 0, 1], [[0, 1]]], [[['BBW', 'WWB', 'WB.', 'BB.'], [], 0, 1], [[0, 0], [0, 1]]]], [[[['W....', '.....', '.....', '.....', '....B'], [], 4, 4], [[4, 4]]], [[['W....', '.....', '.....', '.....', '....B'], [[4, 4], [0, 0]], 0, 0], [[4, 4]]], [[['W....', '.....', '.....', '.....', '....B'], [[4, 4], [4, 4], [0, 0]], 0, 0], [[4, 4]]], [[['.W.B.', 'W.WB.', '.WB..', 'WB...', 'B....'], [], 3, 0], [[3, 0]]], [[['.W.B.', 'W.WB.', '.WB..', 'WB...', 'B....'], [[0, 1]], 4, 2], [[0, 1]]], [[['.W.B.', 'W.WB.', '.WB..', 'WB...', 'B....'], [[2, 2], [1, 3], [1, 3]], 4, 1], [[1, 3], [2, 2]]], [[['WB.B', 'B.B.', '.B..', 'B...'], [[0, 0]], 1, 2], [[0, 0], [1, 2]]], [[['.B.B', '....', 'WWW.', '.W.W', '..B.'], [], 2, 2], [[2, 0], [2, 1], [2, 2], [3, 1]]]], [[[['BBBB', 'B..B', 'B..B', 'BBBB'], [], 2, 3], [[0, 0], [0, 1], [0, 2], [0, 3], [1, 0], [1, 3], [2, 0], [2, 3], [3, 0], [3, 1], [3, 2], [3, 3]]], [[['BBBB', 'B..B', 'B..B', 'BBBB'], [[1, 0], [3, 2], [1, 0], [0, 2]], 3, 1], [[0, 0], [0, 1], [0, 2], [0, 3], [1, 0], [1, 3], [2, 0], [2, 3], [3, 0], [3, 1], [3, 2], [3, 3]]], [[['WWW', 'W.W', 'WWW'], [[0, 1], [1, 2], [1, 2]], 0, 1], []], [[['WWW', 'W.W', 'WWW'], [[0, 1], [0, 0]], 1, 1], [[0, 0], [0, 1]]], [[['WWW', 'W.W', 'WWW'], [[1, 2], [0, 2], [2, 1]], 1, 1], [[0, 2], [1, 2], [2, 1]]], [[['B.W', '...', 'W.B'], [], 2, 2], [[2, 2]]], [[['..W', '.W.', 'W..'], [], 1, 1], [[1, 1]]], [[['.B.B', 'W...', '.BW.', '..BW', '.BWB'], [[1, 0], [1, 0], [4, 1]], 2, 2], [[1, 0], [2, 2], [4, 1]]]], [[[['B.W', '...', 'W.B'], [], 0, 2], [[0, 2]]], [[['.B...', 'B....', '.....', '....W', '...W.'], [], 0, 1], [[0, 1]]], [[['.B...', 'B....', '.....', '....W', '...W.'], [], 4, 3], [[4, 3]]], [[['.B...', 'B....', '.....', '....W', '...W.'], [[1, 0], [1, 0]], 4, 3], [[1, 0], [4, 3]]], [[['BW.', 'BW.', 'BW.'], [], 2, 0], [[0, 0], [1, 0], [2, 0]]], [[['BW.', 'BW.', 'BW.'], [[2, 1], [1, 1], [1, 1]], 0, 0], [[0, 0], [1, 0], [1, 1], [2, 0], [2, 1]]], [[['BWW.', '.W.W', 'W.WW', 'WBWB'], [[3, 2]], 0, 1], [[0, 1], [0, 2], [1, 1], [3, 2]]], [[['BWW.', '.W.W', 'W.WW', 'WBWB'], [[3, 2]], 0, 1], [[0, 1], [0, 2], [1, 1], [3, 2]]]]]
for i, (args, expected) in enumerate(fixtures[N-1]):
    check("dead marks 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
dead marks case 0	`[]`	`[[1, 0]]`	Failed
dead marks case 1	`[[0, 1], [1, 0], [1, 2], [2, 1]]`	`[[0, 1], [1, 0], [1, 2], [2, 1]]`	Passed
dead marks case 2	`[[2, 3], [3, 0]]`	`[[2, 3], [3, 0]]`	Passed
dead marks case 3	`[]`	`[]`	Passed
dead marks case 4	`[[0, 0], [1, 0], [2, 0], [3, 0]]`	`[[0, 0], [1, 0], [2, 0], [3, 0]]`	Passed
dead marks case 5	`[[0, 2]]`	`[[0, 2]]`	Passed
dead marks case 6	`[[0, 2], [1, 2], [2, 2], [3, 2]]`	`[[0, 2], [1, 2], [2, 2], [3, 2]]`	Passed
dead marks case 7	`[]`	`[[2, 3]]`	Failed

SHA-256 / 87ee4b482123f2a13ef984741b6e5b8b1ed7a46d550ad21cb6f2d3d8d3e513fb

2 / The unsuccessful fix

Exit 1

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

N = 1
observations = []
def solve(x):
    board, dead, r, c = x
    n = len(board)
    m = len(board[0])
    col = board[r][c]
    marked = {tuple(p) for p in dead}
    if col == '.':
        return sorted([list(p) for p in marked])
    chain = {(r, c)}
    stack = [(r, c)]
    while stack:
        i, j = stack.pop()
        for p, q in ((i + 1, j), (i, j + 1), (i - 1, j), (i, j - 1), (i + 1, j + 1), (i - 1, j - 1)):
            if 0 <= p < n and 0 <= q < m and board[p][q] == col and (p, q) not in chain:
                chain.add((p, q))
                stack.append((p, q))
    if (r, c) in marked:
        marked -= chain
    else:
        marked |= chain
    return sorted([list(p) for p in marked])
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[[[['.B.', 'B.B', '.B.'], [[1, 0], [1, 2]], 1, 2], [[1, 0]]], [[['.B.', 'B.B', '.B.'], [[1, 2], [0, 1], [1, 0]], 2, 1], [[0, 1], [1, 0], [1, 2], [2, 1]]], [[['B..W', 'B..W', 'B..W', 'B..W'], [[2, 3], [3, 0]], 3, 1], [[2, 3], [3, 0]]], [[['B..W', 'B..W', 'B..W', 'B..W'], [], 1, 1], []], [[['B..W', 'B..W', 'B..W', 'B..W'], [[0, 0]], 3, 0], [[0, 0], [1, 0], [2, 0], [3, 0]]], [[['.BW.', '.BW.', '.BW.', '.BW.'], [[0, 1], [0, 1], [2, 1], [0, 2]], 0, 1], [[0, 2]]], [[['.BW.', '.BW.', '.BW.', '.BW.'], [[0, 2]], 3, 2], [[0, 2], [1, 2], [2, 2], [3, 2]]], [[['..W.', '..W.', 'W..W'], [[0, 2], [2, 3], [0, 2]], 0, 2], [[2, 3]]]], [[[['.BW.', '.BW.', '.BW.', '.BW.'], [], 3, 1], [[0, 1], [1, 1], [2, 1], [3, 1]]], [[['..B..', '..B..', 'BBBBB', 'WWWWW', '..W..'], [[3, 3], [1, 2]], 3, 1], [[1, 2], [3, 0], [3, 1], [3, 2], [3, 3], [3, 4], [4, 2]]], [[['..B..', '..B..', 'BBBBB', 'WWWWW', '..W..'], [[4, 2], [4, 2], [1, 2], [0, 2]], 3, 2], [[0, 2], [1, 2], [3, 0], [3, 1], [3, 2], [3, 3], [3, 4], [4, 2]]], [[['..B..', '..B..', 'BBBBB', 'WWWWW', '..W..'], [], 3, 4], [[3, 0], [3, 1], [3, 2], [3, 3], [3, 4], [4, 2]]], [[['B.B.W', '.B.W.', 'B.BW.', 'BBW.W', '..W..'], [[2, 2]], 4, 0], [[2, 2]]], [[['B.B.W', '.B.W.', 'B.BW.', 'BBW.W', '..W..'], [[2, 3], [3, 0]], 2, 1], [[2, 3], [3, 0]]], [[['.B...', 'B....', '.....', '....W', '...W.'], [], 0, 1], [[0, 1]]], [[['BBW', 'WWB', 'WB.', 'BB.'], [], 0, 1], [[0, 0], [0, 1]]]], [[[['W....', '.....', '.....', '.....', '....B'], [], 4, 4], [[4, 4]]], [[['W....', '.....', '.....', '.....', '....B'], [[4, 4], [0, 0]], 0, 0], [[4, 4]]], [[['W....', '.....', '.....', '.....', '....B'], [[4, 4], [4, 4], [0, 0]], 0, 0], [[4, 4]]], [[['.W.B.', 'W.WB.', '.WB..', 'WB...', 'B....'], [], 3, 0], [[3, 0]]], [[['.W.B.', 'W.WB.', '.WB..', 'WB...', 'B....'], [[0, 1]], 4, 2], [[0, 1]]], [[['.W.B.', 'W.WB.', '.WB..', 'WB...', 'B....'], [[2, 2], [1, 3], [1, 3]], 4, 1], [[1, 3], [2, 2]]], [[['WB.B', 'B.B.', '.B..', 'B...'], [[0, 0]], 1, 2], [[0, 0], [1, 2]]], [[['.B.B', '....', 'WWW.', '.W.W', '..B.'], [], 2, 2], [[2, 0], [2, 1], [2, 2], [3, 1]]]], [[[['BBBB', 'B..B', 'B..B', 'BBBB'], [], 2, 3], [[0, 0], [0, 1], [0, 2], [0, 3], [1, 0], [1, 3], [2, 0], [2, 3], [3, 0], [3, 1], [3, 2], [3, 3]]], [[['BBBB', 'B..B', 'B..B', 'BBBB'], [[1, 0], [3, 2], [1, 0], [0, 2]], 3, 1], [[0, 0], [0, 1], [0, 2], [0, 3], [1, 0], [1, 3], [2, 0], [2, 3], [3, 0], [3, 1], [3, 2], [3, 3]]], [[['WWW', 'W.W', 'WWW'], [[0, 1], [1, 2], [1, 2]], 0, 1], []], [[['WWW', 'W.W', 'WWW'], [[0, 1], [0, 0]], 1, 1], [[0, 0], [0, 1]]], [[['WWW', 'W.W', 'WWW'], [[1, 2], [0, 2], [2, 1]], 1, 1], [[0, 2], [1, 2], [2, 1]]], [[['B.W', '...', 'W.B'], [], 2, 2], [[2, 2]]], [[['..W', '.W.', 'W..'], [], 1, 1], [[1, 1]]], [[['.B.B', 'W...', '.BW.', '..BW', '.BWB'], [[1, 0], [1, 0], [4, 1]], 2, 2], [[1, 0], [2, 2], [4, 1]]]], [[[['B.W', '...', 'W.B'], [], 0, 2], [[0, 2]]], [[['.B...', 'B....', '.....', '....W', '...W.'], [], 0, 1], [[0, 1]]], [[['.B...', 'B....', '.....', '....W', '...W.'], [], 4, 3], [[4, 3]]], [[['.B...', 'B....', '.....', '....W', '...W.'], [[1, 0], [1, 0]], 4, 3], [[1, 0], [4, 3]]], [[['BW.', 'BW.', 'BW.'], [], 2, 0], [[0, 0], [1, 0], [2, 0]]], [[['BW.', 'BW.', 'BW.'], [[2, 1], [1, 1], [1, 1]], 0, 0], [[0, 0], [1, 0], [1, 1], [2, 0], [2, 1]]], [[['BWW.', '.W.W', 'W.WW', 'WBWB'], [[3, 2]], 0, 1], [[0, 1], [0, 2], [1, 1], [3, 2]]], [[['BWW.', '.W.W', 'W.WW', 'WBWB'], [[3, 2]], 0, 1], [[0, 1], [0, 2], [1, 1], [3, 2]]]]]
for i, (args, expected) in enumerate(fixtures[N-1]):
    check("dead marks 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
dead marks case 0	`[[1, 0]]`	`[[1, 0]]`	Passed
dead marks case 1	`[[0, 1], [1, 0], [1, 2], [2, 1]]`	`[[0, 1], [1, 0], [1, 2], [2, 1]]`	Passed
dead marks case 2	`[[2, 3], [3, 0]]`	`[[2, 3], [3, 0]]`	Passed
dead marks case 3	`[]`	`[]`	Passed
dead marks case 4	`[[0, 0], [1, 0], [2, 0], [3, 0]]`	`[[0, 0], [1, 0], [2, 0], [3, 0]]`	Passed
dead marks case 5	`[[0, 2]]`	`[[0, 2]]`	Passed
dead marks case 6	`[[0, 2], [1, 2], [2, 2], [3, 2]]`	`[[0, 2], [1, 2], [2, 2], [3, 2]]`	Passed
dead marks case 7	`[]`	`[[2, 3]]`	Failed

SHA-256 / 97d9603dc9376f6893b41f833fe2a8e6d030e6f1b83a34d39ba85443b5f8cf3d

3 / The verified repair

Exit 0

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

N = 1
observations = []
def solve(x):
    board, dead, r, c = x
    n = len(board)
    m = len(board[0])
    col = board[r][c]
    marked = {tuple(p) for p in dead}
    if col == '.':
        return sorted([list(p) for p in marked])
    chain = {(r, c)}
    stack = [(r, c)]
    while stack:
        i, j = stack.pop()
        for p, q in ((i + 1, j), (i, j + 1), (i - 1, j), (i, j - 1)):
            if 0 <= p < n and 0 <= q < m and board[p][q] == col and (p, q) not in chain:
                chain.add((p, q))
                stack.append((p, q))
    if (r, c) in marked:
        marked -= chain
    else:
        marked |= chain
    return sorted([list(p) for p in marked])
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[[[['.B.', 'B.B', '.B.'], [[1, 0], [1, 2]], 1, 2], [[1, 0]]], [[['.B.', 'B.B', '.B.'], [[1, 2], [0, 1], [1, 0]], 2, 1], [[0, 1], [1, 0], [1, 2], [2, 1]]], [[['B..W', 'B..W', 'B..W', 'B..W'], [[2, 3], [3, 0]], 3, 1], [[2, 3], [3, 0]]], [[['B..W', 'B..W', 'B..W', 'B..W'], [], 1, 1], []], [[['B..W', 'B..W', 'B..W', 'B..W'], [[0, 0]], 3, 0], [[0, 0], [1, 0], [2, 0], [3, 0]]], [[['.BW.', '.BW.', '.BW.', '.BW.'], [[0, 1], [0, 1], [2, 1], [0, 2]], 0, 1], [[0, 2]]], [[['.BW.', '.BW.', '.BW.', '.BW.'], [[0, 2]], 3, 2], [[0, 2], [1, 2], [2, 2], [3, 2]]], [[['..W.', '..W.', 'W..W'], [[0, 2], [2, 3], [0, 2]], 0, 2], [[2, 3]]]], [[[['.BW.', '.BW.', '.BW.', '.BW.'], [], 3, 1], [[0, 1], [1, 1], [2, 1], [3, 1]]], [[['..B..', '..B..', 'BBBBB', 'WWWWW', '..W..'], [[3, 3], [1, 2]], 3, 1], [[1, 2], [3, 0], [3, 1], [3, 2], [3, 3], [3, 4], [4, 2]]], [[['..B..', '..B..', 'BBBBB', 'WWWWW', '..W..'], [[4, 2], [4, 2], [1, 2], [0, 2]], 3, 2], [[0, 2], [1, 2], [3, 0], [3, 1], [3, 2], [3, 3], [3, 4], [4, 2]]], [[['..B..', '..B..', 'BBBBB', 'WWWWW', '..W..'], [], 3, 4], [[3, 0], [3, 1], [3, 2], [3, 3], [3, 4], [4, 2]]], [[['B.B.W', '.B.W.', 'B.BW.', 'BBW.W', '..W..'], [[2, 2]], 4, 0], [[2, 2]]], [[['B.B.W', '.B.W.', 'B.BW.', 'BBW.W', '..W..'], [[2, 3], [3, 0]], 2, 1], [[2, 3], [3, 0]]], [[['.B...', 'B....', '.....', '....W', '...W.'], [], 0, 1], [[0, 1]]], [[['BBW', 'WWB', 'WB.', 'BB.'], [], 0, 1], [[0, 0], [0, 1]]]], [[[['W....', '.....', '.....', '.....', '....B'], [], 4, 4], [[4, 4]]], [[['W....', '.....', '.....', '.....', '....B'], [[4, 4], [0, 0]], 0, 0], [[4, 4]]], [[['W....', '.....', '.....', '.....', '....B'], [[4, 4], [4, 4], [0, 0]], 0, 0], [[4, 4]]], [[['.W.B.', 'W.WB.', '.WB..', 'WB...', 'B....'], [], 3, 0], [[3, 0]]], [[['.W.B.', 'W.WB.', '.WB..', 'WB...', 'B....'], [[0, 1]], 4, 2], [[0, 1]]], [[['.W.B.', 'W.WB.', '.WB..', 'WB...', 'B....'], [[2, 2], [1, 3], [1, 3]], 4, 1], [[1, 3], [2, 2]]], [[['WB.B', 'B.B.', '.B..', 'B...'], [[0, 0]], 1, 2], [[0, 0], [1, 2]]], [[['.B.B', '....', 'WWW.', '.W.W', '..B.'], [], 2, 2], [[2, 0], [2, 1], [2, 2], [3, 1]]]], [[[['BBBB', 'B..B', 'B..B', 'BBBB'], [], 2, 3], [[0, 0], [0, 1], [0, 2], [0, 3], [1, 0], [1, 3], [2, 0], [2, 3], [3, 0], [3, 1], [3, 2], [3, 3]]], [[['BBBB', 'B..B', 'B..B', 'BBBB'], [[1, 0], [3, 2], [1, 0], [0, 2]], 3, 1], [[0, 0], [0, 1], [0, 2], [0, 3], [1, 0], [1, 3], [2, 0], [2, 3], [3, 0], [3, 1], [3, 2], [3, 3]]], [[['WWW', 'W.W', 'WWW'], [[0, 1], [1, 2], [1, 2]], 0, 1], []], [[['WWW', 'W.W', 'WWW'], [[0, 1], [0, 0]], 1, 1], [[0, 0], [0, 1]]], [[['WWW', 'W.W', 'WWW'], [[1, 2], [0, 2], [2, 1]], 1, 1], [[0, 2], [1, 2], [2, 1]]], [[['B.W', '...', 'W.B'], [], 2, 2], [[2, 2]]], [[['..W', '.W.', 'W..'], [], 1, 1], [[1, 1]]], [[['.B.B', 'W...', '.BW.', '..BW', '.BWB'], [[1, 0], [1, 0], [4, 1]], 2, 2], [[1, 0], [2, 2], [4, 1]]]], [[[['B.W', '...', 'W.B'], [], 0, 2], [[0, 2]]], [[['.B...', 'B....', '.....', '....W', '...W.'], [], 0, 1], [[0, 1]]], [[['.B...', 'B....', '.....', '....W', '...W.'], [], 4, 3], [[4, 3]]], [[['.B...', 'B....', '.....', '....W', '...W.'], [[1, 0], [1, 0]], 4, 3], [[1, 0], [4, 3]]], [[['BW.', 'BW.', 'BW.'], [], 2, 0], [[0, 0], [1, 0], [2, 0]]], [[['BW.', 'BW.', 'BW.'], [[2, 1], [1, 1], [1, 1]], 0, 0], [[0, 0], [1, 0], [1, 1], [2, 0], [2, 1]]], [[['BWW.', '.W.W', 'W.WW', 'WBWB'], [[3, 2]], 0, 1], [[0, 1], [0, 2], [1, 1], [3, 2]]], [[['BWW.', '.W.W', 'W.WW', 'WBWB'], [[3, 2]], 0, 1], [[0, 1], [0, 2], [1, 1], [3, 2]]]]]
for i, (args, expected) in enumerate(fixtures[N-1]):
    check("dead marks 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
dead marks case 0	`[[1, 0]]`	`[[1, 0]]`	Passed
dead marks case 1	`[[0, 1], [1, 0], [1, 2], [2, 1]]`	`[[0, 1], [1, 0], [1, 2], [2, 1]]`	Passed
dead marks case 2	`[[2, 3], [3, 0]]`	`[[2, 3], [3, 0]]`	Passed
dead marks case 3	`[]`	`[]`	Passed
dead marks case 4	`[[0, 0], [1, 0], [2, 0], [3, 0]]`	`[[0, 0], [1, 0], [2, 0], [3, 0]]`	Passed
dead marks case 5	`[[0, 2]]`	`[[0, 2]]`	Passed
dead marks case 6	`[[0, 2], [1, 2], [2, 2], [3, 2]]`	`[[0, 2], [1, 2], [2, 2], [3, 2]]`	Passed
dead marks case 7	`[[2, 3]]`	`[[2, 3]]`	Passed

SHA-256 / d7077745ecb1cc84251777358ba0ab132693d6670e213912e325409ac07d61fb

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 2026-09-29T14:50:18.771943+00:00.

Case digest / 5a2da24e33a72bddccad32c5ea5c8d8aa0e34d8e35fc278fc2f1cc45bfbb06b3