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FA-67316 / Railway interlocking logic / Open access

Automatic route setting arbitration: conflict scope · case 01

A candidate conflicting with a later grant is still granted.

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

ROOT CAUSE

Candidates are only checked against the first granted route.

THE FAILURE

Candidates are only checked against the first granted route.

Unsuccessful approach: Checking only the most recent grant misses conflicts with earlier grants.

Case contract

Trains whose eta is at most lookahead_s after now are candidates, including overdue trains (eta before now). Candidates are ordered by class (1 highest), then scheduled time, then id. Routes are granted greedily in that order; a candidate is skipped if its route equals or conflicts with (conflict pairs are unordered) any route already granted. Return granted train ids in grant order.

Why this case matters

Interlocking logic decides whether trains may be given authority; a wrong decision at this point either grants unsafe movements or strands traffic.

1 / The failure

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

N = 1
observations = []
def solve(x):
    now = x['now']
    cand = [t for t in x['trains'] if t['eta'] - now <= x['lookahead_s']]
    cand.sort(key=lambda t: (t['cls'], t['sched'], t['id']))
    pairs = set()
    for a, b in x['conflicts']:
        pairs.add((a, b))
        pairs.add((b, a))
    granted = []
    routes = []
    for t in cand:
        if any(t['route'] == r or (t['route'], r) in pairs for r in routes[:1]):
            continue
        granted.append(t['id'])
        routes.append(t['route'])
    return granted
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[('sampled regression 3', {'now': 100, 'lookahead_s': 60, 'trains': [{'id': '3A00', 'cls': 1, 'sched': 150, 'eta': 160, 'route': 'R1'}, {'id': '2A01', 'cls': 2, 'sched': 100, 'eta': 160, 'route': 'R4'}, {'id': '6A02', 'cls': 1, 'sched': 120, 'eta': 100, 'route': 'R4'}, {'id': '1A03', 'cls': 3, 'sched': 150, 'eta': 80, 'route': 'R1'}, {'id': '9A04', 'cls': 3, 'sched': 100, 'eta': 220, 'route': 'R4'}, {'id': '7A05', 'cls': 3, 'sched': 120, 'eta': 220, 'route': 'R3'}], 'conflicts': [['R2', 'R1'], ['R1', 'R5'], ['R3', 'R4']]}, ['6A02', '3A00']), ('boundary: conflict with an earlier grant', {'now': 100, 'lookahead_s': 60, 'conflicts': [['R1', 'R5']], 'trains': [{'id': '1A01', 'cls': 1, 'sched': 100, 'eta': 110, 'route': 'R1'}, {'id': '1A02', 'cls': 1, 'sched': 110, 'eta': 120, 'route': 'R4'}, {'id': '1A03', 'cls': 1, 'sched': 130, 'eta': 130, 'route': 'R5'}]}, ['1A01', '1A02']), ('sampled regression 21', {'now': 100, 'lookahead_s': 80, 'trains': [{'id': '8A00', 'cls': 3, 'sched': 150, 'eta': 180, 'route': 'R2'}, {'id': '7A01', 'cls': 1, 'sched': 150, 'eta': 100, 'route': 'R5'}, {'id': '3A02', 'cls': 3, 'sched': 150, 'eta': 160, 'route': 'R2'}], 'conflicts': [['R5', 'R1'], ['R4', 'R3'], ['R5', 'R4'], ['R1', 'R2']]}, ['7A01', '3A02']), ('boundary: eta exactly at the lookahead', {'now': 100, 'lookahead_s': 60, 'conflicts': [], 'trains': [{'id': '1A01', 'cls': 1, 'sched': 100, 'eta': 160, 'route': 'R1'}]}, ['1A01']), ('boundary: overdue train', {'now': 100, 'lookahead_s': 60, 'conflicts': [], 'trains': [{'id': '2A01', 'cls': 2, 'sched': 60, 'eta': 70, 'route': 'R2'}]}, ['2A01']), ('control 1', {'now': 100, 'lookahead_s': 60, 'trains': [{'id': '6A00', 'cls': 1, 'sched': 120, 'eta': 400, 'route': 'R1'}, {'id': '7A01', 'cls': 1, 'sched': 120, 'eta': 220, 'route': 'R2'}], 'conflicts': [['R4', 'R3'], ['R2', 'R3'], ['R4', 'R5'], ['R2', 'R1']]}, []), ('sampled regression 4', {'now': 100, 'lookahead_s': 120, 'trains': [{'id': '2A00', 'cls': 2, 'sched': 200, 'eta': 220, 'route': 'R3'}, {'id': '8A01', 'cls': 1, 'sched': 100, 'eta': 80, 'route': 'R5'}, {'id': '7A02', 'cls': 3, 'sched': 100, 'eta': 80, 'route': 'R2'}], 'conflicts': [['R1', 'R5'], ['R1', 'R2'], ['R3', 'R2'], ['R4', 'R5']]}, ['8A01', '2A00']), ('control 7', {'now': 100, 'lookahead_s': 80, 'trains': [{'id': '2A00', 'cls': 1, 'sched': 150, 'eta': 220, 'route': 'R5'}, {'id': '9A01', 'cls': 3, 'sched': 100, 'eta': 160, 'route': 'R1'}], 'conflicts': [['R3', 'R2']]}, ['9A01'])], [('sampled regression 4', {'now': 100, 'lookahead_s': 120, 'trains': [{'id': '2A00', 'cls': 2, 'sched': 200, 'eta': 220, 'route': 'R3'}, {'id': '8A01', 'cls': 1, 'sched': 100, 'eta': 80, 'route': 'R5'}, {'id': '7A02', 'cls': 3, 'sched': 100, 'eta': 80, 'route': 'R2'}], 'conflicts': [['R1', 'R5'], ['R1', 'R2'], ['R3', 'R2'], ['R4', 'R5']]}, ['8A01', '2A00']), ('boundary: conflict with an earlier grant', {'now': 100, 'lookahead_s': 60, 'conflicts': [['R1', 'R5']], 'trains': [{'id': '1A01', 'cls': 1, 'sched': 100, 'eta': 110, 'route': 'R1'}, {'id': '1A02', 'cls': 1, 'sched': 110, 'eta': 120, 'route': 'R4'}, {'id': '1A03', 'cls': 1, 'sched': 130, 'eta': 130, 'route': 'R5'}]}, ['1A01', '1A02']), ('sampled regression 45', {'now': 100, 'lookahead_s': 60, 'trains': [{'id': '6A00', 'cls': 3, 'sched': 150, 'eta': 180, 'route': 'R1'}, {'id': '2A01', 'cls': 3, 'sched': 120, 'eta': 80, 'route': 'R1'}, {'id': '2A02', 'cls': 1, 'sched': 120, 'eta': 400, 'route': 'R1'}, {'id': '5A03', 'cls': 1, 'sched': 120, 'eta': 160, 'route': 'R2'}, {'id': '9A04', 'cls': 3, 'sched': 200, 'eta': 130, 'route': 'R1'}, {'id': '5A05', 'cls': 1, 'sched': 120, 'eta': 130, 'route': 'R1'}], 'conflicts': [['R5', 'R4'], ['R3', 'R2'], ['R1', 'R5'], ['R3', 'R4']]}, ['5A03', '5A05']), ('control 30', {'now': 100, 'lookahead_s': 120, 'trains': [{'id': '8A00', 'cls': 2, 'sched': 120, 'eta': 400, 'route': 'R2'}, {'id': '5A01', 'cls': 2, 'sched': 200, 'eta': 100, 'route': 'R2'}, {'id': '9A02', 'cls': 2, 'sched': 120, 'eta': 220, 'route': 'R2'}, {'id': '7A03', 'cls': 2, 'sched': 150, 'eta': 180, 'route': 'R3'}, {'id': '3A04', 'cls': 2, 'sched': 100, 'eta': 180, 'route': 'R1'}, {'id': '9A05', 'cls': 2, 'sched': 150, 'eta': 130, 'route': 'R2'}], 'conflicts': [['R2', 'R1'], ['R4', 'R5'], ['R4', 'R3'], ['R1', 'R5']]}, ['3A04', '7A03']), ('boundary: class beats schedule', {'now': 100, 'lookahead_s': 60, 'conflicts': [['R1', 'R2']], 'trains': [{'id': '2A01', 'cls': 2, 'sched': 100, 'eta': 110, 'route': 'R1'}, {'id': '1A02', 'cls': 1, 'sched': 150, 'eta': 150, 'route': 'R2'}]}, ['1A02']), ('control 12', {'now': 100, 'lookahead_s': 120, 'trains': [{'id': '8A00', 'cls': 1, 'sched': 100, 'eta': 180, 'route': 'R3'}, {'id': '8A01', 'cls': 2, 'sched': 100, 'eta': 220, 'route': 'R2'}], 'conflicts': [['R3', 'R4']]}, ['8A00', '8A01']), ('control 15', {'now': 100, 'lookahead_s': 60, 'trains': [{'id': '2A00', 'cls': 2, 'sched': 200, 'eta': 180, 'route': 'R5'}, {'id': '6A01', 'cls': 3, 'sched': 150, 'eta': 80, 'route': 'R2'}, {'id': '7A02', 'cls': 3, 'sched': 100, 'eta': 130, 'route': 'R5'}, {'id': '5A03', 'cls': 3, 'sched': 120, 'eta': 160, 'route': 'R1'}], 'conflicts': [['R2', 'R1'], ['R4', 'R5'], ['R1', 'R5']]}, ['7A02', '6A01']), ('control 18', {'now': 100, 'lookahead_s': 120, 'trains': [{'id': '9A00', 'cls': 1, 'sched': 150, 'eta': 220, 'route': 'R4'}, {'id': '8A01', 'cls': 2, 'sched': 100, 'eta': 80, 'route': 'R3'}], 'conflicts': [['R5', 'R4'], ['R1', 'R2'], ['R4', 'R3']]}, ['9A00'])], [('sampled regression 6', {'now': 100, 'lookahead_s': 120, 'trains': [{'id': '2A00', 'cls': 3, 'sched': 120, 'eta': 130, 'route': 'R5'}, {'id': '5A01', 'cls': 3, 'sched': 150, 'eta': 160, 'route': 'R3'}, {'id': '6A02', 'cls': 1, 'sched': 120, 'eta': 100, 'route': 'R3'}, {'id': '5A03', 'cls': 1, 'sched': 120, 'eta': 180, 'route': 'R5'}, {'id': '2A04', 'cls': 1, 'sched': 200, 'eta': 130, 'route': 'R4'}, {'id': '6A05', 'cls': 2, 'sched': 200, 'eta': 220, 'route': 'R1'}], 'conflicts': [['R4', 'R3'], ['R2', 'R1'], ['R5', 'R1'], ['R3', 'R2']]}, ['5A03', '6A02']), ('boundary: conflict with an earlier grant', {'now': 100, 'lookahead_s': 60, 'conflicts': [['R1', 'R5']], 'trains': [{'id': '1A01', 'cls': 1, 'sched': 100, 'eta': 110, 'route': 'R1'}, {'id': '1A02', 'cls': 1, 'sched': 110, 'eta': 120, 'route': 'R4'}, {'id': '1A03', 'cls': 1, 'sched': 130, 'eta': 130, 'route': 'R5'}]}, ['1A01', '1A02']), ('sampled regression 21', {'now': 100, 'lookahead_s': 80, 'trains': [{'id': '8A00', 'cls': 3, 'sched': 150, 'eta': 180, 'route': 'R2'}, {'id': '7A01', 'cls': 1, 'sched': 150, 'eta': 100, 'route': 'R5'}, {'id': '3A02', 'cls': 3, 'sched': 150, 'eta': 160, 'route': 'R2'}], 'conflicts': [['R5', 'R1'], ['R4', 'R3'], ['R5', 'R4'], ['R1', 'R2']]}, ['7A01', '3A02']), ('control 53', {'now': 100, 'lookahead_s': 80, 'trains': [{'id': '1A00', 'cls': 3, 'sched': 120, 'eta': 100, 'route': 'R5'}, {'id': '9A01', 'cls': 2, 'sched': 200, 'eta': 100, 'route': 'R2'}, {'id': '3A02', 'cls': 1, 'sched': 150, 'eta': 400, 'route': 'R5'}, {'id': '5A03', 'cls': 1, 'sched': 200, 'eta': 80, 'route': 'R5'}], 'conflicts': [['R4', 'R5'], ['R4', 'R3'], ['R1', 'R2']]}, ['5A03', '9A01']), ('boundary: reverse-listed conflict granted in reverse', {'now': 100, 'lookahead_s': 60, 'conflicts': [['R3', 'R2']], 'trains': [{'id': '1A01', 'cls': 1, 'sched': 100, 'eta': 110, 'route': 'R3'}, {'id': '1A02', 'cls': 1, 'sched': 120, 'eta': 120, 'route': 'R2'}]}, ['1A01']), ('control 23', {'now': 100, 'lookahead_s': 80, 'trains': [{'id': '9A00', 'cls': 1, 'sched': 200, 'eta': 180, 'route': 'R4'}, {'id': '1A01', 'cls': 2, 'sched': 200, 'eta': 220, 'route': 'R2'}, {'id': '5A02', 'cls': 2, 'sched': 120, 'eta': 160, 'route': 'R5'}, {'id': '2A03', 'cls': 2, 'sched': 150, 'eta': 80, 'route': 'R2'}], 'conflicts': [['R1', 'R5'], ['R2', 'R1']]}, ['9A00', '5A02', '2A03']), ('sampled regression 26', {'now': 100, 'lookahead_s': 80, 'trains': [{'id': '9A00', 'cls': 1, 'sched': 120, 'eta': 160, 'route': 'R2'}, {'id': '7A01', 'cls': 2, 'sched': 100, 'eta': 220, 'route': 'R4'}, {'id': '2A02', 'cls': 1, 'sched': 150, 'eta': 180, 'route': 'R2'}, {'id': '1A03', 'cls': 3, 'sched': 150, 'eta': 130, 'route': 'R1'}, {'id': '7A04', 'cls': 2, 'sched': 120, 'eta': 100, 'route': 'R1'}, {'id': '1A05', 'cls': 2, 'sched': 150, 'eta': 400, 'route': 'R3'}], 'conflicts': [['R1', 'R5']]}, ['9A00', '7A04']), ('control 29', {'now': 100, 'lookahead_s': 80, 'trains': [{'id': '6A00', 'cls': 2, 'sched': 200, 'eta': 80, 'route': 'R5'}, {'id': '8A01', 'cls': 2, 'sched': 120, 'eta': 220, 'route': 'R1'}, {'id': '6A02', 'cls': 1, 'sched': 120, 'eta': 400, 'route': 'R1'}, {'id': '2A03', 'cls': 1, 'sched': 200, 'eta': 400, 'route': 'R3'}], 'conflicts': [['R5', 'R4'], ['R4', 'R3'], ['R2', 'R1'], ['R3', 'R2']]}, ['6A00'])], [('sampled regression 21', {'now': 100, 'lookahead_s': 80, 'trains': [{'id': '8A00', 'cls': 3, 'sched': 150, 'eta': 180, 'route': 'R2'}, {'id': '7A01', 'cls': 1, 'sched': 150, 'eta': 100, 'route': 'R5'}, {'id': '3A02', 'cls': 3, 'sched': 150, 'eta': 160, 'route': 'R2'}], 'conflicts': [['R5', 'R1'], ['R4', 'R3'], ['R5', 'R4'], ['R1', 'R2']]}, ['7A01', '3A02']), ('boundary: conflict with an earlier grant', {'now': 100, 'lookahead_s': 60, 'conflicts': [['R1', 'R5']], 'trains': [{'id': '1A01', 'cls': 1, 'sched': 100, 'eta': 110, 'route': 'R1'}, {'id': '1A02', 'cls': 1, 'sched': 110, 'eta': 120, 'route': 'R4'}, {'id': '1A03', 'cls': 1, 'sched': 130, 'eta': 130, 'route': 'R5'}]}, ['1A01', '1A02']), ('sampled regression 45', {'now': 100, 'lookahead_s': 60, 'trains': [{'id': '6A00', 'cls': 3, 'sched': 150, 'eta': 180, 'route': 'R1'}, {'id': '2A01', 'cls': 3, 'sched': 120, 'eta': 80, 'route': 'R1'}, {'id': '2A02', 'cls': 1, 'sched': 120, 'eta': 400, 'route': 'R1'}, {'id': '5A03', 'cls': 1, 'sched': 120, 'eta': 160, 'route': 'R2'}, {'id': '9A04', 'cls': 3, 'sched': 200, 'eta': 130, 'route': 'R1'}, {'id': '5A05', 'cls': 1, 'sched': 120, 'eta': 130, 'route': 'R1'}], 'conflicts': [['R5', 'R4'], ['R3', 'R2'], ['R1', 'R5'], ['R3', 'R4']]}, ['5A03', '5A05']), ('boundary: late running train keeps schedule order', {'now': 100, 'lookahead_s': 60, 'conflicts': [['R1', 'R2']], 'trains': [{'id': '1A01', 'cls': 1, 'sched': 100, 'eta': 150, 'route': 'R1'}, {'id': '1A02', 'cls': 1, 'sched': 120, 'eta': 105, 'route': 'R2'}]}, ['1A01']), ('boundary: eta exactly at the lookahead', {'now': 100, 'lookahead_s': 60, 'conflicts': [], 'trains': [{'id': '1A01', 'cls': 1, 'sched': 100, 'eta': 160, 'route': 'R1'}]}, ['1A01']), ('control 34', {'now': 100, 'lookahead_s': 80, 'trains': [{'id': '2A00', 'cls': 2, 'sched': 150, 'eta': 160, 'route': 'R5'}, {'id': '6A01', 'cls': 2, 'sched': 200, 'eta': 130, 'route': 'R5'}], 'conflicts': [['R4', 'R3']]}, ['2A00']), ('control 37', {'now': 100, 'lookahead_s': 60, 'trains': [{'id': '4A00', 'cls': 3, 'sched': 120, 'eta': 400, 'route': 'R4'}, {'id': '1A01', 'cls': 1, 'sched': 150, 'eta': 100, 'route': 'R4'}, {'id': '6A02', 'cls': 2, 'sched': 100, 'eta': 130, 'route': 'R4'}, {'id': '3A03', 'cls': 2, 'sched': 150, 'eta': 220, 'route': 'R5'}, {'id': '1A04', 'cls': 3, 'sched': 120, 'eta': 220, 'route': 'R2'}, {'id': '6A05', 'cls': 3, 'sched': 120, 'eta': 180, 'route': 'R1'}], 'conflicts': [['R1', 'R5'], ['R2', 'R1'], ['R3', 'R4']]}, ['1A01']), ('control 40', {'now': 100, 'lookahead_s': 60, 'trains': [{'id': '2A00', 'cls': 2, 'sched': 120, 'eta': 180, 'route': 'R4'}, {'id': '2A01', 'cls': 1, 'sched': 100, 'eta': 400, 'route': 'R4'}, {'id': '8A02', 'cls': 1, 'sched': 150, 'eta': 100, 'route': 'R3'}, {'id': '1A03', 'cls': 2, 'sched': 200, 'eta': 100, 'route': 'R3'}, {'id': '8A04', 'cls': 2, 'sched': 100, 'eta': 130, 'route': 'R4'}, {'id': '3A05', 'cls': 3, 'sched': 120, 'eta': 130, 'route': 'R5'}], 'conflicts': [['R1', 'R5'], ['R2', 'R3'], ['R1', 'R2'], ['R3', 'R4']]}, ['8A02', '3A05'])], [('sampled regression 25', {'now': 100, 'lookahead_s': 80, 'trains': [{'id': '2A00', 'cls': 1, 'sched': 150, 'eta': 160, 'route': 'R1'}, {'id': '7A01', 'cls': 1, 'sched': 150, 'eta': 80, 'route': 'R2'}, {'id': '2A02', 'cls': 1, 'sched': 150, 'eta': 160, 'route': 'R2'}, {'id': '7A03', 'cls': 1, 'sched': 200, 'eta': 400, 'route': 'R2'}, {'id': '1A04', 'cls': 2, 'sched': 120, 'eta': 100, 'route': 'R3'}], 'conflicts': [['R2', 'R3'], ['R4', 'R3']]}, ['2A00', '2A02']), ('boundary: conflict with an earlier grant', {'now': 100, 'lookahead_s': 60, 'conflicts': [['R1', 'R5']], 'trains': [{'id': '1A01', 'cls': 1, 'sched': 100, 'eta': 110, 'route': 'R1'}, {'id': '1A02', 'cls': 1, 'sched': 110, 'eta': 120, 'route': 'R4'}, {'id': '1A03', 'cls': 1, 'sched': 130, 'eta': 130, 'route': 'R5'}]}, ['1A01', '1A02']), ('sampled regression 21', {'now': 100, 'lookahead_s': 80, 'trains': [{'id': '8A00', 'cls': 3, 'sched': 150, 'eta': 180, 'route': 'R2'}, {'id': '7A01', 'cls': 1, 'sched': 150, 'eta': 100, 'route': 'R5'}, {'id': '3A02', 'cls': 3, 'sched': 150, 'eta': 160, 'route': 'R2'}], 'conflicts': [['R5', 'R1'], ['R4', 'R3'], ['R5', 'R4'], ['R1', 'R2']]}, ['7A01', '3A02']), ('control 19', {'now': 100, 'lookahead_s': 80, 'trains': [{'id': '2A00', 'cls': 2, 'sched': 150, 'eta': 80, 'route': 'R3'}, {'id': '8A01', 'cls': 1, 'sched': 120, 'eta': 160, 'route': 'R3'}, {'id': '7A02', 'cls': 2, 'sched': 120, 'eta': 220, 'route': 'R1'}, {'id': '8A03', 'cls': 1, 'sched': 200, 'eta': 80, 'route': 'R5'}], 'conflicts': [['R1', 'R2'], ['R2', 'R3'], ['R4', 'R5'], ['R3', 'R4']]}, ['8A01', '8A03']), ('boundary: eta exactly at the lookahead', {'now': 100, 'lookahead_s': 60, 'conflicts': [], 'trains': [{'id': '1A01', 'cls': 1, 'sched': 100, 'eta': 160, 'route': 'R1'}]}, ['1A01']), ('sampled regression 45', {'now': 100, 'lookahead_s': 60, 'trains': [{'id': '6A00', 'cls': 3, 'sched': 150, 'eta': 180, 'route': 'R1'}, {'id': '2A01', 'cls': 3, 'sched': 120, 'eta': 80, 'route': 'R1'}, {'id': '2A02', 'cls': 1, 'sched': 120, 'eta': 400, 'route': 'R1'}, {'id': '5A03', 'cls': 1, 'sched': 120, 'eta': 160, 'route': 'R2'}, {'id': '9A04', 'cls': 3, 'sched': 200, 'eta': 130, 'route': 'R1'}, {'id': '5A05', 'cls': 1, 'sched': 120, 'eta': 130, 'route': 'R1'}], 'conflicts': [['R5', 'R4'], ['R3', 'R2'], ['R1', 'R5'], ['R3', 'R4']]}, ['5A03', '5A05']), ('control 48', {'now': 100, 'lookahead_s': 80, 'trains': [{'id': '5A00', 'cls': 2, 'sched': 120, 'eta': 100, 'route': 'R1'}, {'id': '2A01', 'cls': 3, 'sched': 100, 'eta': 100, 'route': 'R3'}], 'conflicts': [['R4', 'R5'], ['R3', 'R4'], ['R1', 'R2']]}, ['5A00', '2A01']), ('control 51', {'now': 100, 'lookahead_s': 80, 'trains': [{'id': '5A00', 'cls': 3, 'sched': 150, 'eta': 220, 'route': 'R4'}, {'id': '6A01', 'cls': 1, 'sched': 120, 'eta': 400, 'route': 'R2'}, {'id': '3A02', 'cls': 2, 'sched': 120, 'eta': 160, 'route': 'R4'}, {'id': '6A03', 'cls': 2, 'sched': 100, 'eta': 400, 'route': 'R2'}], 'conflicts': [['R3', 'R2'], ['R4', 'R5']]}, ['3A02'])]]
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
sampled regression 3['6A02', '3A00', '1A03']['6A02', '3A00']Failed
boundary: conflict with an earlier grant['1A01', '1A02']['1A01', '1A02']Passed
sampled regression 21['7A01', '3A02', '8A00']['7A01', '3A02']Failed
boundary: eta exactly at the lookahead['1A01']['1A01']Passed
boundary: overdue train['2A01']['2A01']Passed
control 1[][]Passed
sampled regression 4['8A01', '2A00', '7A02']['8A01', '2A00']Failed
control 7['9A01']['9A01']Passed

SHA-256 / 4765304e7dfed5758d4db4aa43224db182d1bd31a9af5fa9ba1ce9a46bd5e539

2 / The unsuccessful fix

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

N = 1
observations = []
def solve(x):
    now = x['now']
    cand = [t for t in x['trains'] if t['eta'] - now <= x['lookahead_s']]
    cand.sort(key=lambda t: (t['cls'], t['sched'], t['id']))
    pairs = set()
    for a, b in x['conflicts']:
        pairs.add((a, b))
        pairs.add((b, a))
    granted = []
    routes = []
    for t in cand:
        if any(t['route'] == r or (t['route'], r) in pairs for r in routes[-1:]):
            continue
        granted.append(t['id'])
        routes.append(t['route'])
    return granted
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[('sampled regression 3', {'now': 100, 'lookahead_s': 60, 'trains': [{'id': '3A00', 'cls': 1, 'sched': 150, 'eta': 160, 'route': 'R1'}, {'id': '2A01', 'cls': 2, 'sched': 100, 'eta': 160, 'route': 'R4'}, {'id': '6A02', 'cls': 1, 'sched': 120, 'eta': 100, 'route': 'R4'}, {'id': '1A03', 'cls': 3, 'sched': 150, 'eta': 80, 'route': 'R1'}, {'id': '9A04', 'cls': 3, 'sched': 100, 'eta': 220, 'route': 'R4'}, {'id': '7A05', 'cls': 3, 'sched': 120, 'eta': 220, 'route': 'R3'}], 'conflicts': [['R2', 'R1'], ['R1', 'R5'], ['R3', 'R4']]}, ['6A02', '3A00']), ('boundary: conflict with an earlier grant', {'now': 100, 'lookahead_s': 60, 'conflicts': [['R1', 'R5']], 'trains': [{'id': '1A01', 'cls': 1, 'sched': 100, 'eta': 110, 'route': 'R1'}, {'id': '1A02', 'cls': 1, 'sched': 110, 'eta': 120, 'route': 'R4'}, {'id': '1A03', 'cls': 1, 'sched': 130, 'eta': 130, 'route': 'R5'}]}, ['1A01', '1A02']), ('sampled regression 21', {'now': 100, 'lookahead_s': 80, 'trains': [{'id': '8A00', 'cls': 3, 'sched': 150, 'eta': 180, 'route': 'R2'}, {'id': '7A01', 'cls': 1, 'sched': 150, 'eta': 100, 'route': 'R5'}, {'id': '3A02', 'cls': 3, 'sched': 150, 'eta': 160, 'route': 'R2'}], 'conflicts': [['R5', 'R1'], ['R4', 'R3'], ['R5', 'R4'], ['R1', 'R2']]}, ['7A01', '3A02']), ('boundary: eta exactly at the lookahead', {'now': 100, 'lookahead_s': 60, 'conflicts': [], 'trains': [{'id': '1A01', 'cls': 1, 'sched': 100, 'eta': 160, 'route': 'R1'}]}, ['1A01']), ('boundary: overdue train', {'now': 100, 'lookahead_s': 60, 'conflicts': [], 'trains': [{'id': '2A01', 'cls': 2, 'sched': 60, 'eta': 70, 'route': 'R2'}]}, ['2A01']), ('control 1', {'now': 100, 'lookahead_s': 60, 'trains': [{'id': '6A00', 'cls': 1, 'sched': 120, 'eta': 400, 'route': 'R1'}, {'id': '7A01', 'cls': 1, 'sched': 120, 'eta': 220, 'route': 'R2'}], 'conflicts': [['R4', 'R3'], ['R2', 'R3'], ['R4', 'R5'], ['R2', 'R1']]}, []), ('sampled regression 4', {'now': 100, 'lookahead_s': 120, 'trains': [{'id': '2A00', 'cls': 2, 'sched': 200, 'eta': 220, 'route': 'R3'}, {'id': '8A01', 'cls': 1, 'sched': 100, 'eta': 80, 'route': 'R5'}, {'id': '7A02', 'cls': 3, 'sched': 100, 'eta': 80, 'route': 'R2'}], 'conflicts': [['R1', 'R5'], ['R1', 'R2'], ['R3', 'R2'], ['R4', 'R5']]}, ['8A01', '2A00']), ('control 7', {'now': 100, 'lookahead_s': 80, 'trains': [{'id': '2A00', 'cls': 1, 'sched': 150, 'eta': 220, 'route': 'R5'}, {'id': '9A01', 'cls': 3, 'sched': 100, 'eta': 160, 'route': 'R1'}], 'conflicts': [['R3', 'R2']]}, ['9A01'])], [('sampled regression 4', {'now': 100, 'lookahead_s': 120, 'trains': [{'id': '2A00', 'cls': 2, 'sched': 200, 'eta': 220, 'route': 'R3'}, {'id': '8A01', 'cls': 1, 'sched': 100, 'eta': 80, 'route': 'R5'}, {'id': '7A02', 'cls': 3, 'sched': 100, 'eta': 80, 'route': 'R2'}], 'conflicts': [['R1', 'R5'], ['R1', 'R2'], ['R3', 'R2'], ['R4', 'R5']]}, ['8A01', '2A00']), ('boundary: conflict with an earlier grant', {'now': 100, 'lookahead_s': 60, 'conflicts': [['R1', 'R5']], 'trains': [{'id': '1A01', 'cls': 1, 'sched': 100, 'eta': 110, 'route': 'R1'}, {'id': '1A02', 'cls': 1, 'sched': 110, 'eta': 120, 'route': 'R4'}, {'id': '1A03', 'cls': 1, 'sched': 130, 'eta': 130, 'route': 'R5'}]}, ['1A01', '1A02']), ('sampled regression 45', {'now': 100, 'lookahead_s': 60, 'trains': [{'id': '6A00', 'cls': 3, 'sched': 150, 'eta': 180, 'route': 'R1'}, {'id': '2A01', 'cls': 3, 'sched': 120, 'eta': 80, 'route': 'R1'}, {'id': '2A02', 'cls': 1, 'sched': 120, 'eta': 400, 'route': 'R1'}, {'id': '5A03', 'cls': 1, 'sched': 120, 'eta': 160, 'route': 'R2'}, {'id': '9A04', 'cls': 3, 'sched': 200, 'eta': 130, 'route': 'R1'}, {'id': '5A05', 'cls': 1, 'sched': 120, 'eta': 130, 'route': 'R1'}], 'conflicts': [['R5', 'R4'], ['R3', 'R2'], ['R1', 'R5'], ['R3', 'R4']]}, ['5A03', '5A05']), ('control 30', {'now': 100, 'lookahead_s': 120, 'trains': [{'id': '8A00', 'cls': 2, 'sched': 120, 'eta': 400, 'route': 'R2'}, {'id': '5A01', 'cls': 2, 'sched': 200, 'eta': 100, 'route': 'R2'}, {'id': '9A02', 'cls': 2, 'sched': 120, 'eta': 220, 'route': 'R2'}, {'id': '7A03', 'cls': 2, 'sched': 150, 'eta': 180, 'route': 'R3'}, {'id': '3A04', 'cls': 2, 'sched': 100, 'eta': 180, 'route': 'R1'}, {'id': '9A05', 'cls': 2, 'sched': 150, 'eta': 130, 'route': 'R2'}], 'conflicts': [['R2', 'R1'], ['R4', 'R5'], ['R4', 'R3'], ['R1', 'R5']]}, ['3A04', '7A03']), ('boundary: class beats schedule', {'now': 100, 'lookahead_s': 60, 'conflicts': [['R1', 'R2']], 'trains': [{'id': '2A01', 'cls': 2, 'sched': 100, 'eta': 110, 'route': 'R1'}, {'id': '1A02', 'cls': 1, 'sched': 150, 'eta': 150, 'route': 'R2'}]}, ['1A02']), ('control 12', {'now': 100, 'lookahead_s': 120, 'trains': [{'id': '8A00', 'cls': 1, 'sched': 100, 'eta': 180, 'route': 'R3'}, {'id': '8A01', 'cls': 2, 'sched': 100, 'eta': 220, 'route': 'R2'}], 'conflicts': [['R3', 'R4']]}, ['8A00', '8A01']), ('control 15', {'now': 100, 'lookahead_s': 60, 'trains': [{'id': '2A00', 'cls': 2, 'sched': 200, 'eta': 180, 'route': 'R5'}, {'id': '6A01', 'cls': 3, 'sched': 150, 'eta': 80, 'route': 'R2'}, {'id': '7A02', 'cls': 3, 'sched': 100, 'eta': 130, 'route': 'R5'}, {'id': '5A03', 'cls': 3, 'sched': 120, 'eta': 160, 'route': 'R1'}], 'conflicts': [['R2', 'R1'], ['R4', 'R5'], ['R1', 'R5']]}, ['7A02', '6A01']), ('control 18', {'now': 100, 'lookahead_s': 120, 'trains': [{'id': '9A00', 'cls': 1, 'sched': 150, 'eta': 220, 'route': 'R4'}, {'id': '8A01', 'cls': 2, 'sched': 100, 'eta': 80, 'route': 'R3'}], 'conflicts': [['R5', 'R4'], ['R1', 'R2'], ['R4', 'R3']]}, ['9A00'])], [('sampled regression 6', {'now': 100, 'lookahead_s': 120, 'trains': [{'id': '2A00', 'cls': 3, 'sched': 120, 'eta': 130, 'route': 'R5'}, {'id': '5A01', 'cls': 3, 'sched': 150, 'eta': 160, 'route': 'R3'}, {'id': '6A02', 'cls': 1, 'sched': 120, 'eta': 100, 'route': 'R3'}, {'id': '5A03', 'cls': 1, 'sched': 120, 'eta': 180, 'route': 'R5'}, {'id': '2A04', 'cls': 1, 'sched': 200, 'eta': 130, 'route': 'R4'}, {'id': '6A05', 'cls': 2, 'sched': 200, 'eta': 220, 'route': 'R1'}], 'conflicts': [['R4', 'R3'], ['R2', 'R1'], ['R5', 'R1'], ['R3', 'R2']]}, ['5A03', '6A02']), ('boundary: conflict with an earlier grant', {'now': 100, 'lookahead_s': 60, 'conflicts': [['R1', 'R5']], 'trains': [{'id': '1A01', 'cls': 1, 'sched': 100, 'eta': 110, 'route': 'R1'}, {'id': '1A02', 'cls': 1, 'sched': 110, 'eta': 120, 'route': 'R4'}, {'id': '1A03', 'cls': 1, 'sched': 130, 'eta': 130, 'route': 'R5'}]}, ['1A01', '1A02']), ('sampled regression 21', {'now': 100, 'lookahead_s': 80, 'trains': [{'id': '8A00', 'cls': 3, 'sched': 150, 'eta': 180, 'route': 'R2'}, {'id': '7A01', 'cls': 1, 'sched': 150, 'eta': 100, 'route': 'R5'}, {'id': '3A02', 'cls': 3, 'sched': 150, 'eta': 160, 'route': 'R2'}], 'conflicts': [['R5', 'R1'], ['R4', 'R3'], ['R5', 'R4'], ['R1', 'R2']]}, ['7A01', '3A02']), ('control 53', {'now': 100, 'lookahead_s': 80, 'trains': [{'id': '1A00', 'cls': 3, 'sched': 120, 'eta': 100, 'route': 'R5'}, {'id': '9A01', 'cls': 2, 'sched': 200, 'eta': 100, 'route': 'R2'}, {'id': '3A02', 'cls': 1, 'sched': 150, 'eta': 400, 'route': 'R5'}, {'id': '5A03', 'cls': 1, 'sched': 200, 'eta': 80, 'route': 'R5'}], 'conflicts': [['R4', 'R5'], ['R4', 'R3'], ['R1', 'R2']]}, ['5A03', '9A01']), ('boundary: reverse-listed conflict granted in reverse', {'now': 100, 'lookahead_s': 60, 'conflicts': [['R3', 'R2']], 'trains': [{'id': '1A01', 'cls': 1, 'sched': 100, 'eta': 110, 'route': 'R3'}, {'id': '1A02', 'cls': 1, 'sched': 120, 'eta': 120, 'route': 'R2'}]}, ['1A01']), ('control 23', {'now': 100, 'lookahead_s': 80, 'trains': [{'id': '9A00', 'cls': 1, 'sched': 200, 'eta': 180, 'route': 'R4'}, {'id': '1A01', 'cls': 2, 'sched': 200, 'eta': 220, 'route': 'R2'}, {'id': '5A02', 'cls': 2, 'sched': 120, 'eta': 160, 'route': 'R5'}, {'id': '2A03', 'cls': 2, 'sched': 150, 'eta': 80, 'route': 'R2'}], 'conflicts': [['R1', 'R5'], ['R2', 'R1']]}, ['9A00', '5A02', '2A03']), ('sampled regression 26', {'now': 100, 'lookahead_s': 80, 'trains': [{'id': '9A00', 'cls': 1, 'sched': 120, 'eta': 160, 'route': 'R2'}, {'id': '7A01', 'cls': 2, 'sched': 100, 'eta': 220, 'route': 'R4'}, {'id': '2A02', 'cls': 1, 'sched': 150, 'eta': 180, 'route': 'R2'}, {'id': '1A03', 'cls': 3, 'sched': 150, 'eta': 130, 'route': 'R1'}, {'id': '7A04', 'cls': 2, 'sched': 120, 'eta': 100, 'route': 'R1'}, {'id': '1A05', 'cls': 2, 'sched': 150, 'eta': 400, 'route': 'R3'}], 'conflicts': [['R1', 'R5']]}, ['9A00', '7A04']), ('control 29', {'now': 100, 'lookahead_s': 80, 'trains': [{'id': '6A00', 'cls': 2, 'sched': 200, 'eta': 80, 'route': 'R5'}, {'id': '8A01', 'cls': 2, 'sched': 120, 'eta': 220, 'route': 'R1'}, {'id': '6A02', 'cls': 1, 'sched': 120, 'eta': 400, 'route': 'R1'}, {'id': '2A03', 'cls': 1, 'sched': 200, 'eta': 400, 'route': 'R3'}], 'conflicts': [['R5', 'R4'], ['R4', 'R3'], ['R2', 'R1'], ['R3', 'R2']]}, ['6A00'])], [('sampled regression 21', {'now': 100, 'lookahead_s': 80, 'trains': [{'id': '8A00', 'cls': 3, 'sched': 150, 'eta': 180, 'route': 'R2'}, {'id': '7A01', 'cls': 1, 'sched': 150, 'eta': 100, 'route': 'R5'}, {'id': '3A02', 'cls': 3, 'sched': 150, 'eta': 160, 'route': 'R2'}], 'conflicts': [['R5', 'R1'], ['R4', 'R3'], ['R5', 'R4'], ['R1', 'R2']]}, ['7A01', '3A02']), ('boundary: conflict with an earlier grant', {'now': 100, 'lookahead_s': 60, 'conflicts': [['R1', 'R5']], 'trains': [{'id': '1A01', 'cls': 1, 'sched': 100, 'eta': 110, 'route': 'R1'}, {'id': '1A02', 'cls': 1, 'sched': 110, 'eta': 120, 'route': 'R4'}, {'id': '1A03', 'cls': 1, 'sched': 130, 'eta': 130, 'route': 'R5'}]}, ['1A01', '1A02']), ('sampled regression 45', {'now': 100, 'lookahead_s': 60, 'trains': [{'id': '6A00', 'cls': 3, 'sched': 150, 'eta': 180, 'route': 'R1'}, {'id': '2A01', 'cls': 3, 'sched': 120, 'eta': 80, 'route': 'R1'}, {'id': '2A02', 'cls': 1, 'sched': 120, 'eta': 400, 'route': 'R1'}, {'id': '5A03', 'cls': 1, 'sched': 120, 'eta': 160, 'route': 'R2'}, {'id': '9A04', 'cls': 3, 'sched': 200, 'eta': 130, 'route': 'R1'}, {'id': '5A05', 'cls': 1, 'sched': 120, 'eta': 130, 'route': 'R1'}], 'conflicts': [['R5', 'R4'], ['R3', 'R2'], ['R1', 'R5'], ['R3', 'R4']]}, ['5A03', '5A05']), ('boundary: late running train keeps schedule order', {'now': 100, 'lookahead_s': 60, 'conflicts': [['R1', 'R2']], 'trains': [{'id': '1A01', 'cls': 1, 'sched': 100, 'eta': 150, 'route': 'R1'}, {'id': '1A02', 'cls': 1, 'sched': 120, 'eta': 105, 'route': 'R2'}]}, ['1A01']), ('boundary: eta exactly at the lookahead', {'now': 100, 'lookahead_s': 60, 'conflicts': [], 'trains': [{'id': '1A01', 'cls': 1, 'sched': 100, 'eta': 160, 'route': 'R1'}]}, ['1A01']), ('control 34', {'now': 100, 'lookahead_s': 80, 'trains': [{'id': '2A00', 'cls': 2, 'sched': 150, 'eta': 160, 'route': 'R5'}, {'id': '6A01', 'cls': 2, 'sched': 200, 'eta': 130, 'route': 'R5'}], 'conflicts': [['R4', 'R3']]}, ['2A00']), ('control 37', {'now': 100, 'lookahead_s': 60, 'trains': [{'id': '4A00', 'cls': 3, 'sched': 120, 'eta': 400, 'route': 'R4'}, {'id': '1A01', 'cls': 1, 'sched': 150, 'eta': 100, 'route': 'R4'}, {'id': '6A02', 'cls': 2, 'sched': 100, 'eta': 130, 'route': 'R4'}, {'id': '3A03', 'cls': 2, 'sched': 150, 'eta': 220, 'route': 'R5'}, {'id': '1A04', 'cls': 3, 'sched': 120, 'eta': 220, 'route': 'R2'}, {'id': '6A05', 'cls': 3, 'sched': 120, 'eta': 180, 'route': 'R1'}], 'conflicts': [['R1', 'R5'], ['R2', 'R1'], ['R3', 'R4']]}, ['1A01']), ('control 40', {'now': 100, 'lookahead_s': 60, 'trains': [{'id': '2A00', 'cls': 2, 'sched': 120, 'eta': 180, 'route': 'R4'}, {'id': '2A01', 'cls': 1, 'sched': 100, 'eta': 400, 'route': 'R4'}, {'id': '8A02', 'cls': 1, 'sched': 150, 'eta': 100, 'route': 'R3'}, {'id': '1A03', 'cls': 2, 'sched': 200, 'eta': 100, 'route': 'R3'}, {'id': '8A04', 'cls': 2, 'sched': 100, 'eta': 130, 'route': 'R4'}, {'id': '3A05', 'cls': 3, 'sched': 120, 'eta': 130, 'route': 'R5'}], 'conflicts': [['R1', 'R5'], ['R2', 'R3'], ['R1', 'R2'], ['R3', 'R4']]}, ['8A02', '3A05'])], [('sampled regression 25', {'now': 100, 'lookahead_s': 80, 'trains': [{'id': '2A00', 'cls': 1, 'sched': 150, 'eta': 160, 'route': 'R1'}, {'id': '7A01', 'cls': 1, 'sched': 150, 'eta': 80, 'route': 'R2'}, {'id': '2A02', 'cls': 1, 'sched': 150, 'eta': 160, 'route': 'R2'}, {'id': '7A03', 'cls': 1, 'sched': 200, 'eta': 400, 'route': 'R2'}, {'id': '1A04', 'cls': 2, 'sched': 120, 'eta': 100, 'route': 'R3'}], 'conflicts': [['R2', 'R3'], ['R4', 'R3']]}, ['2A00', '2A02']), ('boundary: conflict with an earlier grant', {'now': 100, 'lookahead_s': 60, 'conflicts': [['R1', 'R5']], 'trains': [{'id': '1A01', 'cls': 1, 'sched': 100, 'eta': 110, 'route': 'R1'}, {'id': '1A02', 'cls': 1, 'sched': 110, 'eta': 120, 'route': 'R4'}, {'id': '1A03', 'cls': 1, 'sched': 130, 'eta': 130, 'route': 'R5'}]}, ['1A01', '1A02']), ('sampled regression 21', {'now': 100, 'lookahead_s': 80, 'trains': [{'id': '8A00', 'cls': 3, 'sched': 150, 'eta': 180, 'route': 'R2'}, {'id': '7A01', 'cls': 1, 'sched': 150, 'eta': 100, 'route': 'R5'}, {'id': '3A02', 'cls': 3, 'sched': 150, 'eta': 160, 'route': 'R2'}], 'conflicts': [['R5', 'R1'], ['R4', 'R3'], ['R5', 'R4'], ['R1', 'R2']]}, ['7A01', '3A02']), ('control 19', {'now': 100, 'lookahead_s': 80, 'trains': [{'id': '2A00', 'cls': 2, 'sched': 150, 'eta': 80, 'route': 'R3'}, {'id': '8A01', 'cls': 1, 'sched': 120, 'eta': 160, 'route': 'R3'}, {'id': '7A02', 'cls': 2, 'sched': 120, 'eta': 220, 'route': 'R1'}, {'id': '8A03', 'cls': 1, 'sched': 200, 'eta': 80, 'route': 'R5'}], 'conflicts': [['R1', 'R2'], ['R2', 'R3'], ['R4', 'R5'], ['R3', 'R4']]}, ['8A01', '8A03']), ('boundary: eta exactly at the lookahead', {'now': 100, 'lookahead_s': 60, 'conflicts': [], 'trains': [{'id': '1A01', 'cls': 1, 'sched': 100, 'eta': 160, 'route': 'R1'}]}, ['1A01']), ('sampled regression 45', {'now': 100, 'lookahead_s': 60, 'trains': [{'id': '6A00', 'cls': 3, 'sched': 150, 'eta': 180, 'route': 'R1'}, {'id': '2A01', 'cls': 3, 'sched': 120, 'eta': 80, 'route': 'R1'}, {'id': '2A02', 'cls': 1, 'sched': 120, 'eta': 400, 'route': 'R1'}, {'id': '5A03', 'cls': 1, 'sched': 120, 'eta': 160, 'route': 'R2'}, {'id': '9A04', 'cls': 3, 'sched': 200, 'eta': 130, 'route': 'R1'}, {'id': '5A05', 'cls': 1, 'sched': 120, 'eta': 130, 'route': 'R1'}], 'conflicts': [['R5', 'R4'], ['R3', 'R2'], ['R1', 'R5'], ['R3', 'R4']]}, ['5A03', '5A05']), ('control 48', {'now': 100, 'lookahead_s': 80, 'trains': [{'id': '5A00', 'cls': 2, 'sched': 120, 'eta': 100, 'route': 'R1'}, {'id': '2A01', 'cls': 3, 'sched': 100, 'eta': 100, 'route': 'R3'}], 'conflicts': [['R4', 'R5'], ['R3', 'R4'], ['R1', 'R2']]}, ['5A00', '2A01']), ('control 51', {'now': 100, 'lookahead_s': 80, 'trains': [{'id': '5A00', 'cls': 3, 'sched': 150, 'eta': 220, 'route': 'R4'}, {'id': '6A01', 'cls': 1, 'sched': 120, 'eta': 400, 'route': 'R2'}, {'id': '3A02', 'cls': 2, 'sched': 120, 'eta': 160, 'route': 'R4'}, {'id': '6A03', 'cls': 2, 'sched': 100, 'eta': 400, 'route': 'R2'}], 'conflicts': [['R3', 'R2'], ['R4', 'R5']]}, ['3A02'])]]
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
sampled regression 3['6A02', '3A00', '2A01', '1A03']['6A02', '3A00']Failed
boundary: conflict with an earlier grant['1A01', '1A02', '1A03']['1A01', '1A02']Failed
sampled regression 21['7A01', '3A02']['7A01', '3A02']Passed
boundary: eta exactly at the lookahead['1A01']['1A01']Passed
boundary: overdue train['2A01']['2A01']Passed
control 1[][]Passed
sampled regression 4['8A01', '2A00']['8A01', '2A00']Passed
control 7['9A01']['9A01']Passed

SHA-256 / 7b60974405e0610962ee54d2e8482ce28dfb3616dbe9a6c760173798b24f9a2c

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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.

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Verification & scope

Stipulated toy interlocking contract for a bounded teaching model; it makes no claim of conformance to any railway signalling standard and omits real safety cases. 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 2026-09-29T14:47:51.766808+00:00.

Case digest / 88dc895d59f6dab98b1450c967daf2d970f312e1cccbc40319378f615460491d