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FA-80591 / Bidirectional text layout / Open access

Bracket pair identification: pair ordering · case 01

Bracket pairs come back ordered by closing position.

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

ROOT CAUSE

The pair list is returned in discovery order.

VERIFIED REPAIR

Sort pairs by opener position.

Unsuccessful approach: Sorting by closer is still discovery order.

Case contract

Input [text, classes, stack limit]. Only characters of class ON take part. Openers ( [ { are pushed; on overflow of the stack limit stop and keep pairs found so far. A closer searches the stack from the top for its opener; if found it pairs and discards that entry and everything above; otherwise it is ignored. Return pairs sorted by opener.

Why this case matters

Mixed right-to-left and left-to-right text must resolve levels and visual order exactly, or words, numbers and carets land in the wrong place.

1 / The failure

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

N = 1
observations = []
def solve(x):
    text, classes, limit = x
    OPEN = {'(': ')', '[': ']', '{': '}'}
    CLOSE = {')', ']', '}'}
    stack = []
    pairs = []
    for i, ch in enumerate(text):
        if classes[i] != 'ON':
            continue
        if ch in OPEN:
            if len(stack) >= limit:
                break
            stack.append((OPEN[ch], i))
        elif ch in CLOSE:
            for k in range(len(stack) - 1, -1, -1):
                if stack[k][0] == ch:
                    pairs.append([stack[k][1], i])
                    del stack[k:]
                    break
    return pairs
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[('regression: pair ordering', [']({(}{()a}(})a', ['ON', 'ON', 'ON', 'ON', 'ON', 'ON', 'ON', 'L', 'R', 'L', 'ON', 'ON', 'ON', 'R'], 4], [[1, 12], [2, 4], [5, 11]]), ('regression: pair ordering', ['{a([a)([()][)]', ['L', 'R', 'ON', 'ON', 'R', 'ON', 'ON', 'ON', 'ON', 'ON', 'ON', 'ON', 'ON', 'ON'], 4], [[2, 5], [6, 12], [7, 10], [8, 9]]), ('regression: pair ordering', ['{[{)}((}(((', ['ON', 'ON', 'ON', 'R', 'ON', 'ON', 'R', 'ON', 'ON', 'ON', 'ON'], 4], [[0, 7], [2, 4]]), ('regression: pair ordering', ['a}((())a{', ['R', 'ON', 'ON', 'ON', 'L', 'ON', 'ON', 'R', 'L'], 4], [[2, 6], [3, 5]]), ('overridden bracket ignored', ['(a)', ['R', 'L', 'ON'], 4], []), ('stack overflow stops', ['((()))', ['ON', 'ON', 'ON', 'ON', 'ON', 'ON'], 2], []), ('control layout', [')([((})}(a}{}(', ['ON', 'ON', 'ON', 'ON', 'R', 'ON', 'R', 'ON', 'ON', 'L', 'R', 'ON', 'ON', 'ON'], 2], []), ('control layout', ['({([[{{', ['ON', 'ON', 'ON', 'ON', 'ON', 'ON', 'ON'], 1], [])], [('regression: pair ordering', [')]{(()}[[', ['R', 'ON', 'ON', 'ON', 'ON', 'ON', 'ON', 'ON', 'ON'], 4], [[2, 6], [4, 5]]), ('regression: pair ordering', ['((}}(){{){', ['ON', 'L', 'ON', 'ON', 'ON', 'ON', 'ON', 'ON', 'ON', 'ON'], 3], [[0, 8], [4, 5]]), ('regression: pair ordering', ['([)[{{}]}]({{', ['ON', 'R', 'ON', 'L', 'ON', 'ON', 'ON', 'ON', 'ON', 'R', 'ON', 'ON', 'L'], 2], [[0, 2], [4, 8], [5, 6]]), ('regression: pair ordering', ['a}((())a{', ['R', 'ON', 'ON', 'ON', 'L', 'ON', 'ON', 'R', 'L'], 4], [[2, 6], [3, 5]]), ('overridden bracket ignored', ['(a)', ['R', 'L', 'ON'], 4], []), ('mismatched inner bracket', ['([)]', ['ON', 'ON', 'ON', 'ON'], 4], [[0, 2]]), ('control layout', ['((aa]{[(a{', ['R', 'ON', 'R', 'L', 'ON', 'ON', 'ON', 'R', 'R', 'ON'], 4], []), ('control layout', ['){}', ['ON', 'ON', 'L'], 2], [])], [('regression: pair ordering', ['))]{{])a{})}a)', ['ON', 'ON', 'R', 'R', 'ON', 'ON', 'ON', 'L', 'ON', 'ON', 'ON', 'ON', 'R', 'ON'], 2], [[4, 11], [8, 9]]), ('regression: pair ordering', ['{[()}{]a', ['L', 'ON', 'ON', 'ON', 'L', 'ON', 'ON', 'L'], 2], [[1, 6], [2, 3]]), ('regression: pair ordering', ['((][{]a{{)}', ['ON', 'ON', 'ON', 'ON', 'ON', 'ON', 'L', 'R', 'L', 'ON', 'R'], 4], [[1, 9], [3, 5]]), ('regression: pair ordering', [']({(}{()a}(})a', ['ON', 'ON', 'ON', 'ON', 'ON', 'ON', 'ON', 'L', 'R', 'L', 'ON', 'ON', 'ON', 'R'], 4], [[1, 12], [2, 4], [5, 11]]), ('stack overflow stops', ['((()))', ['ON', 'ON', 'ON', 'ON', 'ON', 'ON'], 2], []), ('mismatched inner bracket', ['([)]', ['ON', 'ON', 'ON', 'ON'], 4], [[0, 2]]), ('control layout', ['[[{({[}[)](', ['ON', 'ON', 'ON', 'ON', 'L', 'R', 'ON', 'ON', 'ON', 'ON', 'ON'], 1], []), ('control layout', ['a]]{)a((](a', ['R', 'ON', 'R', 'ON', 'ON', 'L', 'ON', 'ON', 'ON', 'ON', 'L'], 2], [])], [('regression: pair ordering', ['{(a)]]})a}(][[', ['ON', 'ON', 'L', 'ON', 'ON', 'ON', 'ON', 'ON', 'R', 'ON', 'ON', 'ON', 'ON', 'ON'], 4], [[0, 6], [1, 3]]), ('regression: pair ordering', ['{a([a)([()][)]', ['L', 'R', 'ON', 'ON', 'R', 'ON', 'ON', 'ON', 'ON', 'ON', 'ON', 'ON', 'ON', 'ON'], 4], [[2, 5], [6, 12], [7, 10], [8, 9]]), ('regression: pair ordering', ['((}}(){{){', ['ON', 'L', 'ON', 'ON', 'ON', 'ON', 'ON', 'ON', 'ON', 'ON'], 3], [[0, 8], [4, 5]]), ('regression: pair ordering', [')a{{a}]}({', ['L', 'L', 'ON', 'ON', 'L', 'ON', 'ON', 'ON', 'ON', 'ON'], 4], [[2, 7], [3, 5]]), ('stack overflow stops', ['((()))', ['ON', 'ON', 'ON', 'ON', 'ON', 'ON'], 2], []), ('overridden bracket ignored', ['(a)', ['R', 'L', 'ON'], 4], []), ('control layout', ['()(}a}(', ['ON', 'ON', 'ON', 'ON', 'R', 'ON', 'ON'], 3], [[0, 1]]), ('control layout', ['(a)a(((()', ['ON', 'L', 'ON', 'R', 'ON', 'ON', 'ON', 'ON', 'ON'], 3], [[0, 2]])], [('regression: pair ordering', [')a{{a}]}({', ['L', 'L', 'ON', 'ON', 'L', 'ON', 'ON', 'ON', 'ON', 'ON'], 4], [[2, 7], [3, 5]]), ('regression: pair ordering', ['}[(]]([aa()(}]', ['ON', 'ON', 'ON', 'ON', 'ON', 'ON', 'ON', 'L', 'L', 'ON', 'ON', 'ON', 'ON', 'ON'], 3], [[1, 3], [6, 13], [9, 10]]), ('regression: pair ordering', ['((}}(){{){', ['ON', 'L', 'ON', 'ON', 'ON', 'ON', 'ON', 'ON', 'ON', 'ON'], 3], [[0, 8], [4, 5]]), ('regression: pair ordering', [']({(}{()a}(})a', ['ON', 'ON', 'ON', 'ON', 'ON', 'ON', 'ON', 'L', 'R', 'L', 'ON', 'ON', 'ON', 'R'], 4], [[1, 12], [2, 4], [5, 11]]), ('overridden bracket ignored', ['(a)', ['R', 'L', 'ON'], 4], []), ('stack overflow stops', ['((()))', ['ON', 'ON', 'ON', 'ON', 'ON', 'ON'], 2], []), ('control layout', ['[[}{(](', ['R', 'ON', 'R', 'ON', 'L', 'ON', 'ON'], 4], [[1, 5]]), ('control layout', ['([(]}}))(}a(', ['L', 'R', 'ON', 'ON', 'ON', 'ON', 'ON', 'ON', 'ON', 'ON', 'R', 'ON'], 3], [[2, 6]])]]
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
regression: pair ordering[[2, 4], [5, 11], [1, 12]][[1, 12], [2, 4], [5, 11]]Failed
regression: pair ordering[[2, 5], [8, 9], [7, 10], [6, 12]][[2, 5], [6, 12], [7, 10], [8, 9]]Failed
regression: pair ordering[[2, 4], [0, 7]][[0, 7], [2, 4]]Failed
regression: pair ordering[[3, 5], [2, 6]][[2, 6], [3, 5]]Failed
overridden bracket ignored[][]Passed
stack overflow stops[][]Passed
control layout[][]Passed
control layout[][]Passed

SHA-256 / fda81e140977bdd95f92097cf90e732cba61dc4841cea3d28ef755c10a083b56

2 / The unsuccessful fix

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

N = 1
observations = []
def solve(x):
    text, classes, limit = x
    OPEN = {'(': ')', '[': ']', '{': '}'}
    CLOSE = {')', ']', '}'}
    stack = []
    pairs = []
    for i, ch in enumerate(text):
        if classes[i] != 'ON':
            continue
        if ch in OPEN:
            if len(stack) >= limit:
                break
            stack.append((OPEN[ch], i))
        elif ch in CLOSE:
            for k in range(len(stack) - 1, -1, -1):
                if stack[k][0] == ch:
                    pairs.append([stack[k][1], i])
                    del stack[k:]
                    break
    return sorted(pairs, key=lambda p: p[1])
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[('regression: pair ordering', [']({(}{()a}(})a', ['ON', 'ON', 'ON', 'ON', 'ON', 'ON', 'ON', 'L', 'R', 'L', 'ON', 'ON', 'ON', 'R'], 4], [[1, 12], [2, 4], [5, 11]]), ('regression: pair ordering', ['{a([a)([()][)]', ['L', 'R', 'ON', 'ON', 'R', 'ON', 'ON', 'ON', 'ON', 'ON', 'ON', 'ON', 'ON', 'ON'], 4], [[2, 5], [6, 12], [7, 10], [8, 9]]), ('regression: pair ordering', ['{[{)}((}(((', ['ON', 'ON', 'ON', 'R', 'ON', 'ON', 'R', 'ON', 'ON', 'ON', 'ON'], 4], [[0, 7], [2, 4]]), ('regression: pair ordering', ['a}((())a{', ['R', 'ON', 'ON', 'ON', 'L', 'ON', 'ON', 'R', 'L'], 4], [[2, 6], [3, 5]]), ('overridden bracket ignored', ['(a)', ['R', 'L', 'ON'], 4], []), ('stack overflow stops', ['((()))', ['ON', 'ON', 'ON', 'ON', 'ON', 'ON'], 2], []), ('control layout', [')([((})}(a}{}(', ['ON', 'ON', 'ON', 'ON', 'R', 'ON', 'R', 'ON', 'ON', 'L', 'R', 'ON', 'ON', 'ON'], 2], []), ('control layout', ['({([[{{', ['ON', 'ON', 'ON', 'ON', 'ON', 'ON', 'ON'], 1], [])], [('regression: pair ordering', [')]{(()}[[', ['R', 'ON', 'ON', 'ON', 'ON', 'ON', 'ON', 'ON', 'ON'], 4], [[2, 6], [4, 5]]), ('regression: pair ordering', ['((}}(){{){', ['ON', 'L', 'ON', 'ON', 'ON', 'ON', 'ON', 'ON', 'ON', 'ON'], 3], [[0, 8], [4, 5]]), ('regression: pair ordering', ['([)[{{}]}]({{', ['ON', 'R', 'ON', 'L', 'ON', 'ON', 'ON', 'ON', 'ON', 'R', 'ON', 'ON', 'L'], 2], [[0, 2], [4, 8], [5, 6]]), ('regression: pair ordering', ['a}((())a{', ['R', 'ON', 'ON', 'ON', 'L', 'ON', 'ON', 'R', 'L'], 4], [[2, 6], [3, 5]]), ('overridden bracket ignored', ['(a)', ['R', 'L', 'ON'], 4], []), ('mismatched inner bracket', ['([)]', ['ON', 'ON', 'ON', 'ON'], 4], [[0, 2]]), ('control layout', ['((aa]{[(a{', ['R', 'ON', 'R', 'L', 'ON', 'ON', 'ON', 'R', 'R', 'ON'], 4], []), ('control layout', ['){}', ['ON', 'ON', 'L'], 2], [])], [('regression: pair ordering', ['))]{{])a{})}a)', ['ON', 'ON', 'R', 'R', 'ON', 'ON', 'ON', 'L', 'ON', 'ON', 'ON', 'ON', 'R', 'ON'], 2], [[4, 11], [8, 9]]), ('regression: pair ordering', ['{[()}{]a', ['L', 'ON', 'ON', 'ON', 'L', 'ON', 'ON', 'L'], 2], [[1, 6], [2, 3]]), ('regression: pair ordering', ['((][{]a{{)}', ['ON', 'ON', 'ON', 'ON', 'ON', 'ON', 'L', 'R', 'L', 'ON', 'R'], 4], [[1, 9], [3, 5]]), ('regression: pair ordering', [']({(}{()a}(})a', ['ON', 'ON', 'ON', 'ON', 'ON', 'ON', 'ON', 'L', 'R', 'L', 'ON', 'ON', 'ON', 'R'], 4], [[1, 12], [2, 4], [5, 11]]), ('stack overflow stops', ['((()))', ['ON', 'ON', 'ON', 'ON', 'ON', 'ON'], 2], []), ('mismatched inner bracket', ['([)]', ['ON', 'ON', 'ON', 'ON'], 4], [[0, 2]]), ('control layout', ['[[{({[}[)](', ['ON', 'ON', 'ON', 'ON', 'L', 'R', 'ON', 'ON', 'ON', 'ON', 'ON'], 1], []), ('control layout', ['a]]{)a((](a', ['R', 'ON', 'R', 'ON', 'ON', 'L', 'ON', 'ON', 'ON', 'ON', 'L'], 2], [])], [('regression: pair ordering', ['{(a)]]})a}(][[', ['ON', 'ON', 'L', 'ON', 'ON', 'ON', 'ON', 'ON', 'R', 'ON', 'ON', 'ON', 'ON', 'ON'], 4], [[0, 6], [1, 3]]), ('regression: pair ordering', ['{a([a)([()][)]', ['L', 'R', 'ON', 'ON', 'R', 'ON', 'ON', 'ON', 'ON', 'ON', 'ON', 'ON', 'ON', 'ON'], 4], [[2, 5], [6, 12], [7, 10], [8, 9]]), ('regression: pair ordering', ['((}}(){{){', ['ON', 'L', 'ON', 'ON', 'ON', 'ON', 'ON', 'ON', 'ON', 'ON'], 3], [[0, 8], [4, 5]]), ('regression: pair ordering', [')a{{a}]}({', ['L', 'L', 'ON', 'ON', 'L', 'ON', 'ON', 'ON', 'ON', 'ON'], 4], [[2, 7], [3, 5]]), ('stack overflow stops', ['((()))', ['ON', 'ON', 'ON', 'ON', 'ON', 'ON'], 2], []), ('overridden bracket ignored', ['(a)', ['R', 'L', 'ON'], 4], []), ('control layout', ['()(}a}(', ['ON', 'ON', 'ON', 'ON', 'R', 'ON', 'ON'], 3], [[0, 1]]), ('control layout', ['(a)a(((()', ['ON', 'L', 'ON', 'R', 'ON', 'ON', 'ON', 'ON', 'ON'], 3], [[0, 2]])], [('regression: pair ordering', [')a{{a}]}({', ['L', 'L', 'ON', 'ON', 'L', 'ON', 'ON', 'ON', 'ON', 'ON'], 4], [[2, 7], [3, 5]]), ('regression: pair ordering', ['}[(]]([aa()(}]', ['ON', 'ON', 'ON', 'ON', 'ON', 'ON', 'ON', 'L', 'L', 'ON', 'ON', 'ON', 'ON', 'ON'], 3], [[1, 3], [6, 13], [9, 10]]), ('regression: pair ordering', ['((}}(){{){', ['ON', 'L', 'ON', 'ON', 'ON', 'ON', 'ON', 'ON', 'ON', 'ON'], 3], [[0, 8], [4, 5]]), ('regression: pair ordering', [']({(}{()a}(})a', ['ON', 'ON', 'ON', 'ON', 'ON', 'ON', 'ON', 'L', 'R', 'L', 'ON', 'ON', 'ON', 'R'], 4], [[1, 12], [2, 4], [5, 11]]), ('overridden bracket ignored', ['(a)', ['R', 'L', 'ON'], 4], []), ('stack overflow stops', ['((()))', ['ON', 'ON', 'ON', 'ON', 'ON', 'ON'], 2], []), ('control layout', ['[[}{(](', ['R', 'ON', 'R', 'ON', 'L', 'ON', 'ON'], 4], [[1, 5]]), ('control layout', ['([(]}}))(}a(', ['L', 'R', 'ON', 'ON', 'ON', 'ON', 'ON', 'ON', 'ON', 'ON', 'R', 'ON'], 3], [[2, 6]])]]
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
regression: pair ordering[[2, 4], [5, 11], [1, 12]][[1, 12], [2, 4], [5, 11]]Failed
regression: pair ordering[[2, 5], [8, 9], [7, 10], [6, 12]][[2, 5], [6, 12], [7, 10], [8, 9]]Failed
regression: pair ordering[[2, 4], [0, 7]][[0, 7], [2, 4]]Failed
regression: pair ordering[[3, 5], [2, 6]][[2, 6], [3, 5]]Failed
overridden bracket ignored[][]Passed
stack overflow stops[][]Passed
control layout[][]Passed
control layout[][]Passed

SHA-256 / 6f3c3d711a6e652130914fbfb918d30d4e6beade7a5338aa9ea3a8f3cd851023

3 / The verified repair

Exit 0
"""Failure Map reference implementation. Python standard library only."""
import json

N = 1
observations = []
def solve(x):
    text, classes, limit = x
    OPEN = {'(': ')', '[': ']', '{': '}'}
    CLOSE = {')', ']', '}'}
    stack = []
    pairs = []
    for i, ch in enumerate(text):
        if classes[i] != 'ON':
            continue
        if ch in OPEN:
            if len(stack) >= limit:
                break
            stack.append((OPEN[ch], i))
        elif ch in CLOSE:
            for k in range(len(stack) - 1, -1, -1):
                if stack[k][0] == ch:
                    pairs.append([stack[k][1], i])
                    del stack[k:]
                    break
    return sorted(pairs)
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[('regression: pair ordering', [']({(}{()a}(})a', ['ON', 'ON', 'ON', 'ON', 'ON', 'ON', 'ON', 'L', 'R', 'L', 'ON', 'ON', 'ON', 'R'], 4], [[1, 12], [2, 4], [5, 11]]), ('regression: pair ordering', ['{a([a)([()][)]', ['L', 'R', 'ON', 'ON', 'R', 'ON', 'ON', 'ON', 'ON', 'ON', 'ON', 'ON', 'ON', 'ON'], 4], [[2, 5], [6, 12], [7, 10], [8, 9]]), ('regression: pair ordering', ['{[{)}((}(((', ['ON', 'ON', 'ON', 'R', 'ON', 'ON', 'R', 'ON', 'ON', 'ON', 'ON'], 4], [[0, 7], [2, 4]]), ('regression: pair ordering', ['a}((())a{', ['R', 'ON', 'ON', 'ON', 'L', 'ON', 'ON', 'R', 'L'], 4], [[2, 6], [3, 5]]), ('overridden bracket ignored', ['(a)', ['R', 'L', 'ON'], 4], []), ('stack overflow stops', ['((()))', ['ON', 'ON', 'ON', 'ON', 'ON', 'ON'], 2], []), ('control layout', [')([((})}(a}{}(', ['ON', 'ON', 'ON', 'ON', 'R', 'ON', 'R', 'ON', 'ON', 'L', 'R', 'ON', 'ON', 'ON'], 2], []), ('control layout', ['({([[{{', ['ON', 'ON', 'ON', 'ON', 'ON', 'ON', 'ON'], 1], [])], [('regression: pair ordering', [')]{(()}[[', ['R', 'ON', 'ON', 'ON', 'ON', 'ON', 'ON', 'ON', 'ON'], 4], [[2, 6], [4, 5]]), ('regression: pair ordering', ['((}}(){{){', ['ON', 'L', 'ON', 'ON', 'ON', 'ON', 'ON', 'ON', 'ON', 'ON'], 3], [[0, 8], [4, 5]]), ('regression: pair ordering', ['([)[{{}]}]({{', ['ON', 'R', 'ON', 'L', 'ON', 'ON', 'ON', 'ON', 'ON', 'R', 'ON', 'ON', 'L'], 2], [[0, 2], [4, 8], [5, 6]]), ('regression: pair ordering', ['a}((())a{', ['R', 'ON', 'ON', 'ON', 'L', 'ON', 'ON', 'R', 'L'], 4], [[2, 6], [3, 5]]), ('overridden bracket ignored', ['(a)', ['R', 'L', 'ON'], 4], []), ('mismatched inner bracket', ['([)]', ['ON', 'ON', 'ON', 'ON'], 4], [[0, 2]]), ('control layout', ['((aa]{[(a{', ['R', 'ON', 'R', 'L', 'ON', 'ON', 'ON', 'R', 'R', 'ON'], 4], []), ('control layout', ['){}', ['ON', 'ON', 'L'], 2], [])], [('regression: pair ordering', ['))]{{])a{})}a)', ['ON', 'ON', 'R', 'R', 'ON', 'ON', 'ON', 'L', 'ON', 'ON', 'ON', 'ON', 'R', 'ON'], 2], [[4, 11], [8, 9]]), ('regression: pair ordering', ['{[()}{]a', ['L', 'ON', 'ON', 'ON', 'L', 'ON', 'ON', 'L'], 2], [[1, 6], [2, 3]]), ('regression: pair ordering', ['((][{]a{{)}', ['ON', 'ON', 'ON', 'ON', 'ON', 'ON', 'L', 'R', 'L', 'ON', 'R'], 4], [[1, 9], [3, 5]]), ('regression: pair ordering', [']({(}{()a}(})a', ['ON', 'ON', 'ON', 'ON', 'ON', 'ON', 'ON', 'L', 'R', 'L', 'ON', 'ON', 'ON', 'R'], 4], [[1, 12], [2, 4], [5, 11]]), ('stack overflow stops', ['((()))', ['ON', 'ON', 'ON', 'ON', 'ON', 'ON'], 2], []), ('mismatched inner bracket', ['([)]', ['ON', 'ON', 'ON', 'ON'], 4], [[0, 2]]), ('control layout', ['[[{({[}[)](', ['ON', 'ON', 'ON', 'ON', 'L', 'R', 'ON', 'ON', 'ON', 'ON', 'ON'], 1], []), ('control layout', ['a]]{)a((](a', ['R', 'ON', 'R', 'ON', 'ON', 'L', 'ON', 'ON', 'ON', 'ON', 'L'], 2], [])], [('regression: pair ordering', ['{(a)]]})a}(][[', ['ON', 'ON', 'L', 'ON', 'ON', 'ON', 'ON', 'ON', 'R', 'ON', 'ON', 'ON', 'ON', 'ON'], 4], [[0, 6], [1, 3]]), ('regression: pair ordering', ['{a([a)([()][)]', ['L', 'R', 'ON', 'ON', 'R', 'ON', 'ON', 'ON', 'ON', 'ON', 'ON', 'ON', 'ON', 'ON'], 4], [[2, 5], [6, 12], [7, 10], [8, 9]]), ('regression: pair ordering', ['((}}(){{){', ['ON', 'L', 'ON', 'ON', 'ON', 'ON', 'ON', 'ON', 'ON', 'ON'], 3], [[0, 8], [4, 5]]), ('regression: pair ordering', [')a{{a}]}({', ['L', 'L', 'ON', 'ON', 'L', 'ON', 'ON', 'ON', 'ON', 'ON'], 4], [[2, 7], [3, 5]]), ('stack overflow stops', ['((()))', ['ON', 'ON', 'ON', 'ON', 'ON', 'ON'], 2], []), ('overridden bracket ignored', ['(a)', ['R', 'L', 'ON'], 4], []), ('control layout', ['()(}a}(', ['ON', 'ON', 'ON', 'ON', 'R', 'ON', 'ON'], 3], [[0, 1]]), ('control layout', ['(a)a(((()', ['ON', 'L', 'ON', 'R', 'ON', 'ON', 'ON', 'ON', 'ON'], 3], [[0, 2]])], [('regression: pair ordering', [')a{{a}]}({', ['L', 'L', 'ON', 'ON', 'L', 'ON', 'ON', 'ON', 'ON', 'ON'], 4], [[2, 7], [3, 5]]), ('regression: pair ordering', ['}[(]]([aa()(}]', ['ON', 'ON', 'ON', 'ON', 'ON', 'ON', 'ON', 'L', 'L', 'ON', 'ON', 'ON', 'ON', 'ON'], 3], [[1, 3], [6, 13], [9, 10]]), ('regression: pair ordering', ['((}}(){{){', ['ON', 'L', 'ON', 'ON', 'ON', 'ON', 'ON', 'ON', 'ON', 'ON'], 3], [[0, 8], [4, 5]]), ('regression: pair ordering', [']({(}{()a}(})a', ['ON', 'ON', 'ON', 'ON', 'ON', 'ON', 'ON', 'L', 'R', 'L', 'ON', 'ON', 'ON', 'R'], 4], [[1, 12], [2, 4], [5, 11]]), ('overridden bracket ignored', ['(a)', ['R', 'L', 'ON'], 4], []), ('stack overflow stops', ['((()))', ['ON', 'ON', 'ON', 'ON', 'ON', 'ON'], 2], []), ('control layout', ['[[}{(](', ['R', 'ON', 'R', 'ON', 'L', 'ON', 'ON'], 4], [[1, 5]]), ('control layout', ['([(]}}))(}a(', ['L', 'R', 'ON', 'ON', 'ON', 'ON', 'ON', 'ON', 'ON', 'ON', 'R', 'ON'], 3], [[2, 6]])]]
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
regression: pair ordering[[1, 12], [2, 4], [5, 11]][[1, 12], [2, 4], [5, 11]]Passed
regression: pair ordering[[2, 5], [6, 12], [7, 10], [8, 9]][[2, 5], [6, 12], [7, 10], [8, 9]]Passed
regression: pair ordering[[0, 7], [2, 4]][[0, 7], [2, 4]]Passed
regression: pair ordering[[2, 6], [3, 5]][[2, 6], [3, 5]]Passed
overridden bracket ignored[][]Passed
stack overflow stops[][]Passed
control layout[][]Passed
control layout[][]Passed

SHA-256 / a4a7db39414bd6caef31a9f50686c2ec2d929a8bad05d86452413759d4d0b49f

Verification & scope

A deterministic toy bidi model over stipulated class labels and integer levels; it is inspired by, but does not claim conformance to, any published algorithm. 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 2026-09-29T14:49:55.430010+00:00.

Case digest / dac384a04c0d1a50115346959c8b41a31f0ed8117d605c6fea128193c99b5682