{"abstract":"Back-to-back cues climb to a second row instead of reusing the bottom row.","category":"Subtitle cue timing","checks":8,"contract":"Assign overlapping cues to display rows. Cues are processed by (start, input index); a row is free at time t when the last cue placed there ended at or before t (end exclusive). Each cue takes the lowest free row, or opens a new row. Return the row of each cue in input order.","contract_signature":"cues","evaluation_group":"w2-subtitle-cue-timing-row-stacking","failed_approach":"Freeing rows one millisecond early lets overlapping cues share a row.","family":"w2-subtitle-cue-timing-row-stacking-row-free-test","id":"FA-78041","implementations":{"attempt":{"sha256":"76505a770c297cea106099e641c203bfc15bd6be2d36785e3cecc51823af979b","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(cues):\n    order=sorted(range(len(cues)),key=lambda i:(cues[i][0],i))\n    row_end=[]\n    rows=[0]*len(cues)\n    for i in order:\n        s,e=cues[i]\n        for r in range(len(row_end)):\n            if row_end[r]-1<=s:\n                row_end[r]=e\n                rows[i]=r\n                break\n        else:\n            row_end.append(e)\n            rows[i]=len(row_end)-1\n    return rows\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\nfixtures = [[('regression: row free test', [[[0, 100], [100, 200]]], [0, 0]), ('regression variant: row free test', [[[1000, 1900], [100, 1000], [500, 900], [500, 501], [500, 900], [200, 300]]], [0, 0, 1, 2, 3, 1]), ('partial repair probe: row free test', [[[1000, 1900], [200, 500], [0, 1], [100, 500], [500, 700], [0, 900]]], [0, 2, 0, 0, 0, 1]), ('partial repair variant: row free test', [[[300, 301], [300, 400]]], [0, 1]), ('boundary control', [[[0, 100]]], [0]), ('normal control', [[[1000, 1001]]], [0]), ('normal control', [[[1000, 1400]]], [0]), ('normal control', [[[0, 300], [0, 400]]], [0, 1])], [('regression: row free test', [[[0, 300], [100, 200], [200, 400]]], [0, 1, 1]), ('regression variant: row free test', [[[100, 1000], [500, 600], [200, 500], [200, 500], [0, 200], [100, 101]]], [1, 0, 0, 2, 0, 2]), ('partial repair probe: row free test', [[[200, 201], [300, 500], [200, 201], [1000, 1300], [300, 400], [0, 200]]], [0, 0, 1, 0, 1, 0]), ('partial repair variant: row free test', [[[300, 600], [100, 400], [1000, 1001], [100, 101], [0, 400], [100, 400]]], [2, 1, 0, 2, 0, 3]), ('boundary control', [[[0, 100]]], [0]), ('normal control', [[[0, 900]]], [0]), ('normal control', [[[100, 500], [200, 300], [1000, 1100]]], [0, 1, 0]), ('normal control', [[[100, 101]]], [0])], [('regression: row free test', [[[0, 500], [0, 100], [100, 200]]], [0, 1, 1]), ('regression variant: row free test', [[[200, 600], [100, 200], [1000, 1400]]], [0, 0, 0]), ('partial repair probe: row free test', [[[100, 1000], [300, 301], [300, 500], [500, 501]]], [0, 1, 2, 1]), ('partial repair variant: row free test', [[[0, 100], [0, 1], [0, 400], [0, 900], [0, 100]]], [0, 1, 2, 3, 4]), ('boundary control', [[[0, 100]]], [0]), ('normal control', [[[200, 500], [1000, 1100], [1000, 1200], [0, 900]]], [1, 0, 1, 0]), ('normal control', [[[1000, 1100], [200, 500]]], [0, 0]), ('normal control', [[[1000, 1300], [500, 800], [0, 400], [100, 400]]], [0, 0, 0, 1])], [('regression: row free test', [[[100, 300], [300, 500], [100, 500]]], [0, 0, 1]), ('regression variant: row free test', [[[500, 800], [300, 400], [1000, 1200], [300, 600], [500, 600], [200, 300]]], [0, 0, 0, 1, 2, 0]), ('partial repair probe: row free test', [[[0, 400], [200, 1100], [500, 700], [0, 1], [0, 900], [200, 201]]], [0, 1, 0, 1, 2, 3]), ('partial repair variant: row free test', [[[1000, 1001], [0, 300], [300, 600], [1000, 1001], [0, 1], [0, 900]]], [0, 0, 0, 1, 1, 2]), ('boundary control', [[[0, 100]]], [0]), ('normal control', [[[300, 1200]]], [0]), ('normal control', [[[0, 900], [500, 1400]]], [0, 1]), ('normal control', [[[500, 600], [0, 1]]], [0, 0])], [('regression: row free test', [[[200, 500], [0, 900], [1000, 1100], [500, 900]]], [1, 0, 0, 1]), ('regression variant: row free test', [[[1000, 1900], [200, 500], [0, 1], [100, 500], [500, 700], [0, 900]]], [0, 2, 0, 0, 0, 1]), ('partial repair probe: row free test', [[[1000, 1400], [300, 700], [1000, 1001], [0, 400], [300, 1200], [1000, 1100]]], [0, 1, 1, 0, 2, 3]), ('partial repair variant: row free test', [[[0, 200], [300, 700], [1000, 1001], [1000, 1001], [100, 300]]], [0, 0, 0, 1, 1]), ('boundary control', [[[0, 100]]], [0]), ('normal control', [[[300, 600]]], [0]), ('normal control', [[[0, 100], [0, 900], [300, 700], [0, 200], [200, 400]]], [0, 1, 2, 2, 0]), ('normal control', [[[0, 900], [500, 800], [300, 600]]], [0, 2, 1])]]\nfor label, args, expected in fixtures[N-1]:\n    check(label, solve(*args), expected)\nprint(json.dumps({\"observations\": observations, \"passed\": all(x[\"passed\"] for x in observations)}, ensure_ascii=False))\nraise SystemExit(0 if all(x[\"passed\"] for x in observations) else 1)\n"},"broken":{"sha256":"d0b4883ce1e7e0bd83e439400c60a1e1e6400770d069d2aa7dfc97137c97a160","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(cues):\n    order=sorted(range(len(cues)),key=lambda i:(cues[i][0],i))\n    row_end=[]\n    rows=[0]*len(cues)\n    for i in order:\n        s,e=cues[i]\n        for r in range(len(row_end)):\n            if row_end[r]<s:\n                row_end[r]=e\n                rows[i]=r\n                break\n        else:\n            row_end.append(e)\n            rows[i]=len(row_end)-1\n    return rows\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\nfixtures = [[('regression: row free test', [[[0, 100], [100, 200]]], [0, 0]), ('regression variant: row free test', [[[1000, 1900], [100, 1000], [500, 900], [500, 501], [500, 900], [200, 300]]], [0, 0, 1, 2, 3, 1]), ('partial repair probe: row free test', [[[1000, 1900], [200, 500], [0, 1], [100, 500], [500, 700], [0, 900]]], [0, 2, 0, 0, 0, 1]), ('partial repair variant: row free test', [[[300, 301], [300, 400]]], [0, 1]), ('boundary control', [[[0, 100]]], [0]), ('normal control', [[[1000, 1001]]], [0]), ('normal control', [[[1000, 1400]]], [0]), ('normal control', [[[0, 300], [0, 400]]], [0, 1])], [('regression: row free test', [[[0, 300], [100, 200], [200, 400]]], [0, 1, 1]), ('regression variant: row free test', [[[100, 1000], [500, 600], [200, 500], [200, 500], [0, 200], [100, 101]]], [1, 0, 0, 2, 0, 2]), ('partial repair probe: row free test', [[[200, 201], [300, 500], [200, 201], [1000, 1300], [300, 400], [0, 200]]], [0, 0, 1, 0, 1, 0]), ('partial repair variant: row free test', [[[300, 600], [100, 400], [1000, 1001], [100, 101], [0, 400], [100, 400]]], [2, 1, 0, 2, 0, 3]), ('boundary control', [[[0, 100]]], [0]), ('normal control', [[[0, 900]]], [0]), ('normal control', [[[100, 500], [200, 300], [1000, 1100]]], [0, 1, 0]), ('normal control', [[[100, 101]]], [0])], [('regression: row free test', [[[0, 500], [0, 100], [100, 200]]], [0, 1, 1]), ('regression variant: row free test', [[[200, 600], [100, 200], [1000, 1400]]], [0, 0, 0]), ('partial repair probe: row free test', [[[100, 1000], [300, 301], [300, 500], [500, 501]]], [0, 1, 2, 1]), ('partial repair variant: row free test', [[[0, 100], [0, 1], [0, 400], [0, 900], [0, 100]]], [0, 1, 2, 3, 4]), ('boundary control', [[[0, 100]]], [0]), ('normal control', [[[200, 500], [1000, 1100], [1000, 1200], [0, 900]]], [1, 0, 1, 0]), ('normal control', [[[1000, 1100], [200, 500]]], [0, 0]), ('normal control', [[[1000, 1300], [500, 800], [0, 400], [100, 400]]], [0, 0, 0, 1])], [('regression: row free test', [[[100, 300], [300, 500], [100, 500]]], [0, 0, 1]), ('regression variant: row free test', [[[500, 800], [300, 400], [1000, 1200], [300, 600], [500, 600], [200, 300]]], [0, 0, 0, 1, 2, 0]), ('partial repair probe: row free test', [[[0, 400], [200, 1100], [500, 700], [0, 1], [0, 900], [200, 201]]], [0, 1, 0, 1, 2, 3]), ('partial repair variant: row free test', [[[1000, 1001], [0, 300], [300, 600], [1000, 1001], [0, 1], [0, 900]]], [0, 0, 0, 1, 1, 2]), ('boundary control', [[[0, 100]]], [0]), ('normal control', [[[300, 1200]]], [0]), ('normal control', [[[0, 900], [500, 1400]]], [0, 1]), ('normal control', [[[500, 600], [0, 1]]], [0, 0])], [('regression: row free test', [[[200, 500], [0, 900], [1000, 1100], [500, 900]]], [1, 0, 0, 1]), ('regression variant: row free test', [[[1000, 1900], [200, 500], [0, 1], [100, 500], [500, 700], [0, 900]]], [0, 2, 0, 0, 0, 1]), ('partial repair probe: row free test', [[[1000, 1400], [300, 700], [1000, 1001], [0, 400], [300, 1200], [1000, 1100]]], [0, 1, 1, 0, 2, 3]), ('partial repair variant: row free test', [[[0, 200], [300, 700], [1000, 1001], [1000, 1001], [100, 300]]], [0, 0, 0, 1, 1]), ('boundary control', [[[0, 100]]], [0]), ('normal control', [[[300, 600]]], [0]), ('normal control', [[[0, 100], [0, 900], [300, 700], [0, 200], [200, 400]]], [0, 1, 2, 2, 0]), ('normal control', [[[0, 900], [500, 800], [300, 600]]], [0, 2, 1])]]\nfor label, args, expected in fixtures[N-1]:\n    check(label, solve(*args), expected)\nprint(json.dumps({\"observations\": observations, \"passed\": all(x[\"passed\"] for x in observations)}, ensure_ascii=False))\nraise SystemExit(0 if all(x[\"passed\"] for x in observations) else 1)\n"}},"limitations":"A deterministic bounded teaching model with a stipulated toy contract; it does not claim conformance to any subtitle 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.","method":"Deterministic executable model with adversarial boundary fixtures.","provenance":{"created_by":"Failure Map","dependencies":"Python standard library","family":"w2-subtitle-cue-timing-row-stacking-row-free-test","generated_at":"2026-09-29T14:49:31.428320+00:00","license":"CC0-1.0","python":"3.12.14","seed":1,"split":"open-access"},"relevance":"Subtitle timing defects shift, hide or overlap captions that viewers depend on for comprehension and accessibility.","root_cause":"A row is considered busy at the instant its previous cue ends.","sha256":"6ca14ce295b279c9691c094b012bc21888b8266f03636e8b6374778b8751ceef","title":"Overlapping cue row stacking: row free test · case 01","variant":1,"variant_policy":"Five numbered records share a model and may reuse boundary fixtures.","verified":true,"visibility":"public","verification":{"attempt":{"elapsed_ms":41.476,"exit_code":1,"observations":[{"actual":[0,0],"check":"regression: row free test","expected":[0,0],"passed":true},{"actual":[0,0,1,2,2,1],"check":"regression variant: row free test","expected":[0,0,1,2,3,1],"passed":false},{"actual":[0,2,0,1,1,0],"check":"partial repair probe: row free test","expected":[0,2,0,0,0,1],"passed":false},{"actual":[0,0],"check":"partial repair variant: row free test","expected":[0,1],"passed":false},{"actual":[0],"check":"boundary control","expected":[0],"passed":true},{"actual":[0],"check":"normal control","expected":[0],"passed":true},{"actual":[0],"check":"normal control","expected":[0],"passed":true},{"actual":[0,1],"check":"normal control","expected":[0,1],"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"regression: row free test\", \"actual\": [0, 0], \"expected\": [0, 0], \"passed\": true}, {\"check\": \"regression variant: row free test\", \"actual\": [0, 0, 1, 2, 2, 1], \"expected\": [0, 0, 1, 2, 3, 1], \"passed\": false}, {\"check\": \"partial repair probe: row free test\", \"actual\": [0, 2, 0, 1, 1, 0], \"expected\": [0, 2, 0, 0, 0, 1], \"passed\": false}, {\"check\": \"partial repair variant: row free test\", \"actual\": [0, 0], \"expected\": [0, 1], \"passed\": false}, {\"check\": \"boundary control\", \"actual\": [0], \"expected\": [0], \"passed\": true}, {\"check\": \"normal control\", \"actual\": [0], \"expected\": [0], \"passed\": true}, {\"check\": \"normal control\", \"actual\": [0], \"expected\": [0], \"passed\": true}, {\"check\": \"normal control\", \"actual\": [0, 1], \"expected\": [0, 1], \"passed\": true}], \"passed\": false}\n"},"broken":{"elapsed_ms":40.965,"exit_code":1,"observations":[{"actual":[0,1],"check":"regression: row free test","expected":[0,0],"passed":false},{"actual":[1,0,1,2,3,1],"check":"regression variant: row free test","expected":[0,0,1,2,3,1],"passed":false},{"actual":[0,2,0,0,3,1],"check":"partial repair probe: row free test","expected":[0,2,0,0,0,1],"passed":false},{"actual":[0,1],"check":"partial repair variant: row free test","expected":[0,1],"passed":true},{"actual":[0],"check":"boundary control","expected":[0],"passed":true},{"actual":[0],"check":"normal control","expected":[0],"passed":true},{"actual":[0],"check":"normal control","expected":[0],"passed":true},{"actual":[0,1],"check":"normal control","expected":[0,1],"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"regression: row free test\", \"actual\": [0, 1], \"expected\": [0, 0], \"passed\": false}, {\"check\": \"regression variant: row free test\", \"actual\": [1, 0, 1, 2, 3, 1], \"expected\": [0, 0, 1, 2, 3, 1], \"passed\": false}, {\"check\": \"partial repair probe: row free test\", \"actual\": [0, 2, 0, 0, 3, 1], \"expected\": [0, 2, 0, 0, 0, 1], \"passed\": false}, {\"check\": \"partial repair variant: row free test\", \"actual\": [0, 1], \"expected\": [0, 1], \"passed\": true}, {\"check\": \"boundary control\", \"actual\": [0], \"expected\": [0], \"passed\": true}, {\"check\": \"normal control\", \"actual\": [0], \"expected\": [0], \"passed\": true}, {\"check\": \"normal control\", \"actual\": [0], \"expected\": [0], \"passed\": true}, {\"check\": \"normal control\", \"actual\": [0, 1], \"expected\": [0, 1], \"passed\": true}], \"passed\": false}\n"}},"member_only":{"stages":["fixed"],"fields":["implementations.fixed","verification.fixed","harness","repair"],"note":"The verified repair, its recorded checks, the repair description, and the scoring harness are available to members."}}