FA-68646 / Toll and parking fee computation / Open access

One-way bridge toll with frequent-user discount: carpools of exactly the minimum occupancy are charged · case 01

One-way bridge toll with frequent-user discount returns a wrong result when carpools of exactly the minimum occupancy are charged.

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

ROOT CAUSE

Vehicles at exactly the carpool minimum pay the toll.

VERIFIED REPAIR

Restore the carpool threshold rule so that the step reads `if occ >= x['carpool_min']:`.

Unsuccessful approach: A hard-coded three ignores two-person carpool rules.

Case contract

Input {trips: [[month index, direction, occupancy]], toll_dir, base, threshold, discount_pct, carpool_min}. Only trips in toll_dir are tolled. Carpools (occupancy >= carpool_min) are free and do not count. Paid trips are counted per month index (no carry-over between months); trips beyond threshold in a month pay floor(base*(100-discount)/100).

Why this case matters

Fee engines bill customers in integer cents; a wrong boundary, rounding stage or cap scope silently over- or under-charges.

1 / The failure

Exit 1

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

N = 1
observations = []
def solve(x):
    counts = {}
    total = 0
    for month, d, occ in x['trips']:
        if d != x['toll_dir']:
            continue
        if occ > x['carpool_min']:
            continue
        k = counts.get(month, 0) + 1
        counts[month] = k
        if k > x['threshold']:
            total += x['base'] * (100 - x['discount_pct']) // 100
        else:
            total += x['base']
    return total
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[({'trips': [[2, 'E', 1], [1, 'E', 4], [1, 'E', 1]], 'toll_dir': 'W', 'base': 850, 'threshold': 4, 'discount_pct': 40, 'carpool_min': 2}, 0), ({'trips': [[2, 'W', 1], [13, 'E', 2], [13, 'E', 1], [1, 'E', 2], [1, 'W', 3], [1, 'E', 1], [1, 'E', 3], [1, 'W', 2], [13, 'E', 2], [2, 'W', 1], [1, 'E', 4], [1, 'W', 1], [2, 'W', 1], [2, 'E', 3]], 'toll_dir': 'E', 'base': 600, 'threshold': 1, 'discount_pct': 25, 'carpool_min': 2}, 1200), ({'trips': [[1, 'E', 4], [1, 'W', 2], [1, 'E', 3], [2, 'E', 3], [1, 'W', 2], [1, 'E', 4], [13, 'W', 1], [1, 'W', 4], [1, 'E', 1]], 'toll_dir': 'E', 'base': 850, 'threshold': 1, 'discount_pct': 40, 'carpool_min': 2}, 850), ({'trips': [[2, 'W', 1], [1, 'W', 1], [1, 'E', 1], [1, 'E', 1], [1, 'E', 1], [1, 'W', 2], [1, 'W', 2]], 'toll_dir': 'W', 'base': 725, 'threshold': 2, 'discount_pct': 40, 'carpool_min': 3}, 2610), ({'trips': [[1, 'W', 1], [1, 'W', 3], [2, 'E', 1], [1, 'E', 4], [1, 'E', 3], [2, 'E', 4], [1, 'E', 4], [1, 'E', 4], [13, 'E', 3], [1, 'W', 1], [2, 'E', 3]], 'toll_dir': 'W', 'base': 600, 'threshold': 3, 'discount_pct': 40, 'carpool_min': 3}, 1200), ({'trips': [[13, 'W', 1], [1, 'E', 3], [1, 'E', 2], [13, 'W', 2], [1, 'E', 3], [13, 'W', 1], [13, 'W', 1], [13, 'W', 1], [1, 'W', 1], [2, 'W', 2], [1, 'E', 1], [13, 'E', 3], [1, 'W', 2]], 'toll_dir': 'W', 'base': 600, 'threshold': 2, 'discount_pct': 25, 'carpool_min': 2}, 2700), ({'trips': [[1, 'W', 1], [1, 'W', 1], [1, 'W', 3], [1, 'W', 1], [13, 'W', 1]], 'toll_dir': 'W', 'base': 725, 'threshold': 2, 'discount_pct': 33, 'carpool_min': 3}, 2660), ({'trips': [[13, 'W', 1], [13, 'E', 1], [1, 'E', 1], [1, 'W', 1], [13, 'W', 3], [2, 'E', 1]], 'toll_dir': 'W', 'base': 725, 'threshold': 3, 'discount_pct': 40, 'carpool_min': 2}, 1450)], [({'trips': [[1, 'W', 1], [1, 'W', 1], [1, 'W', 3], [1, 'W', 1], [13, 'W', 1]], 'toll_dir': 'W', 'base': 725, 'threshold': 2, 'discount_pct': 33, 'carpool_min': 3}, 2660), ({'trips': [[13, 'W', 2], [13, 'E', 4], [13, 'E', 4], [13, 'E', 2], [13, 'E', 1]], 'toll_dir': 'W', 'base': 850, 'threshold': 5, 'discount_pct': 40, 'carpool_min': 3}, 850), ({'trips': [[1, 'E', 1], [1, 'E', 1], [2, 'W', 3]], 'toll_dir': 'E', 'base': 850, 'threshold': 1, 'discount_pct': 25, 'carpool_min': 2}, 1487), ({'trips': [[13, 'W', 2], [13, 'W', 1], [13, 'W', 1], [13, 'W', 4], [1, 'W', 1]], 'toll_dir': 'E', 'base': 600, 'threshold': 4, 'discount_pct': 33, 'carpool_min': 2}, 0), ({'trips': [[1, 'E', 1], [1, 'W', 1], [1, 'E', 1], [2, 'E', 2], [2, 'W', 2], [1, 'W', 1]], 'toll_dir': 'W', 'base': 600, 'threshold': 1, 'discount_pct': 33, 'carpool_min': 2}, 1002), ({'trips': [[13, 'W', 2], [1, 'E', 2], [2, 'W', 1], [13, 'W', 4], [1, 'E', 3], [1, 'W', 3], [1, 'E', 1], [2, 'E', 2]], 'toll_dir': 'W', 'base': 850, 'threshold': 1, 'discount_pct': 33, 'carpool_min': 2}, 850), ({'trips': [[13, 'W', 1], [1, 'E', 2], [13, 'W', 1], [1, 'W', 1], [1, 'E', 1], [1, 'E', 2], [1, 'E', 3], [2, 'E', 1], [1, 'W', 2], [1, 'W', 1], [1, 'E', 1], [2, 'W', 1], [1, 'W', 1], [2, 'E', 1], [1, 'E', 3], [1, 'E', 2]], 'toll_dir': 'W', 'base': 850, 'threshold': 3, 'discount_pct': 40, 'carpool_min': 3}, 5610), ({'trips': [[1, 'W', 2], [1, 'W', 1], [13, 'W', 1], [2, 'W', 1]], 'toll_dir': 'E', 'base': 725, 'threshold': 2, 'discount_pct': 40, 'carpool_min': 2}, 0)], [({'trips': [[1, 'W', 1], [1, 'W', 1], [1, 'W', 3], [1, 'W', 1], [13, 'W', 1]], 'toll_dir': 'W', 'base': 725, 'threshold': 2, 'discount_pct': 33, 'carpool_min': 3}, 2660), ({'trips': [[1, 'W', 1], [2, 'W', 4], [1, 'E', 3], [1, 'E', 3], [1, 'W', 1], [13, 'E', 1], [1, 'E', 4], [2, 'E', 1], [1, 'W', 2], [2, 'E', 1], [2, 'E', 3]], 'toll_dir': 'E', 'base': 850, 'threshold': 3, 'discount_pct': 25, 'carpool_min': 2}, 2550), ({'trips': [[13, 'E', 1], [1, 'W', 1], [13, 'E', 2], [1, 'E', 1], [1, 'W', 1], [1, 'W', 2], [1, 'W', 4], [1, 'W', 1], [2, 'W', 1]], 'toll_dir': 'E', 'base': 600, 'threshold': 1, 'discount_pct': 25, 'carpool_min': 3}, 1650), ({'trips': [[1, 'W', 2], [1, 'W', 4], [1, 'E', 1], [13, 'E', 1], [1, 'E', 1], [2, 'E', 1], [2, 'W', 1], [2, 'W', 1], [2, 'E', 1]], 'toll_dir': 'W', 'base': 850, 'threshold': 5, 'discount_pct': 40, 'carpool_min': 2}, 1700), ({'trips': [[13, 'E', 1], [13, 'E', 2], [1, 'W', 2], [1, 'E', 3], [2, 'W', 4], [1, 'W', 2]], 'toll_dir': 'W', 'base': 725, 'threshold': 4, 'discount_pct': 40, 'carpool_min': 2}, 0), ({'trips': [[13, 'E', 3], [1, 'E', 3], [1, 'E', 3], [1, 'E', 1], [1, 'E', 1], [1, 'W', 4]], 'toll_dir': 'W', 'base': 600, 'threshold': 5, 'discount_pct': 25, 'carpool_min': 2}, 0), ({'trips': [[1, 'E', 2], [1, 'W', 1], [1, 'W', 1], [1, 'W', 1], [13, 'W', 3], [13, 'E', 4], [1, 'W', 3], [1, 'E', 3], [1, 'E', 1], [1, 'W', 1], [1, 'E', 3]], 'toll_dir': 'W', 'base': 725, 'threshold': 3, 'discount_pct': 25, 'carpool_min': 2}, 2718), ({'trips': [[2, 'E', 3], [2, 'W', 1], [1, 'E', 2], [1, 'E', 2], [2, 'W', 1], [1, 'E', 1]], 'toll_dir': 'W', 'base': 850, 'threshold': 3, 'discount_pct': 33, 'carpool_min': 2}, 1700)], [({'trips': [[1, 'W', 1], [1, 'W', 1], [1, 'W', 3], [1, 'W', 1], [13, 'W', 1]], 'toll_dir': 'W', 'base': 725, 'threshold': 2, 'discount_pct': 33, 'carpool_min': 3}, 2660), ({'trips': [[13, 'E', 3], [1, 'E', 1], [1, 'W', 1], [2, 'E', 1], [1, 'E', 1], [13, 'W', 1], [13, 'E', 1], [13, 'E', 3]], 'toll_dir': 'W', 'base': 850, 'threshold': 2, 'discount_pct': 25, 'carpool_min': 3}, 1700), ({'trips': [[2, 'E', 2], [2, 'E', 4], [13, 'E', 2], [1, 'W', 2], [2, 'W', 3], [2, 'E', 1], [2, 'W', 1], [2, 'E', 1], [2, 'E', 2], [1, 'W', 2], [13, 'W', 1]], 'toll_dir': 'E', 'base': 600, 'threshold': 3, 'discount_pct': 40, 'carpool_min': 3}, 2760), ({'trips': [[13, 'W', 1], [2, 'W', 1], [1, 'W', 2], [1, 'W', 1], [13, 'W', 1], [1, 'E', 1], [1, 'W', 1], [1, 'W', 4], [1, 'W', 1], [2, 'E', 1]], 'toll_dir': 'E', 'base': 725, 'threshold': 1, 'discount_pct': 25, 'carpool_min': 2}, 1450), ({'trips': [[1, 'E', 1], [13, 'W', 1], [1, 'E', 2], [1, 'W', 3], [1, 'W', 1], [2, 'W', 3], [1, 'E', 1], [1, 'E', 1], [2, 'E', 2]], 'toll_dir': 'E', 'base': 725, 'threshold': 3, 'discount_pct': 33, 'carpool_min': 2}, 2175), ({'trips': [[1, 'E', 1], [2, 'W', 2], [2, 'E', 1], [2, 'W', 1], [1, 'E', 2], [13, 'E', 1], [1, 'W', 2], [1, 'W', 1]], 'toll_dir': 'E', 'base': 600, 'threshold': 5, 'discount_pct': 40, 'carpool_min': 3}, 2400), ({'trips': [[1, 'E', 1], [13, 'E', 4], [2, 'E', 1], [13, 'W', 4], [1, 'W', 1], [1, 'W', 1]], 'toll_dir': 'W', 'base': 850, 'threshold': 1, 'discount_pct': 40, 'carpool_min': 3}, 1360), ({'trips': [[13, 'E', 4], [1, 'E', 4], [1, 'W', 1], [1, 'W', 1], [1, 'E', 1], [1, 'W', 2], [13, 'E', 1], [1, 'E', 3], [1, 'W', 3], [1, 'W', 2], [13, 'E', 1]], 'toll_dir': 'W', 'base': 600, 'threshold': 5, 'discount_pct': 40, 'carpool_min': 2}, 1200)], [({'trips': [[13, 'E', 4], [13, 'W', 1], [1, 'W', 1], [1, 'E', 1]], 'toll_dir': 'W', 'base': 725, 'threshold': 2, 'discount_pct': 25, 'carpool_min': 3}, 1450), ({'trips': [[1, 'W', 1], [13, 'E', 1], [1, 'E', 1], [2, 'W', 1], [1, 'E', 1], [1, 'E', 2], [2, 'E', 2], [1, 'W', 1], [1, 'E', 2]], 'toll_dir': 'E', 'base': 600, 'threshold': 2, 'discount_pct': 40, 'carpool_min': 2}, 1800), ({'trips': [[2, 'E', 4], [2, 'W', 1], [2, 'E', 1], [1, 'E', 3], [1, 'W', 2], [13, 'W', 1], [2, 'W', 4], [1, 'E', 1], [1, 'E', 1], [2, 'W', 1], [13, 'W', 2], [1, 'E', 2], [2, 'E', 2], [1, 'W', 1], [1, 'W', 3]], 'toll_dir': 'E', 'base': 725, 'threshold': 2, 'discount_pct': 40, 'carpool_min': 3}, 3335), ({'trips': [[1, 'E', 2], [2, 'W', 3], [1, 'W', 1], [2, 'E', 3], [13, 'E', 1], [1, 'E', 3], [1, 'W', 2], [1, 'W', 1], [1, 'E', 3], [1, 'W', 3], [13, 'E', 1], [13, 'E', 3], [1, 'W', 1], [1, 'W', 1], [1, 'W', 4]], 'toll_dir': 'W', 'base': 600, 'threshold': 1, 'discount_pct': 40, 'carpool_min': 3}, 2040), ({'trips': [[1, 'W', 1], [1, 'W', 1], [1, 'W', 3], [1, 'W', 1], [13, 'W', 1]], 'toll_dir': 'W', 'base': 725, 'threshold': 2, 'discount_pct': 33, 'carpool_min': 3}, 2660), ({'trips': [[1, 'E', 2], [1, 'W', 1], [1, 'E', 3], [2, 'W', 2], [1, 'W', 1], [1, 'E', 1], [2, 'W', 4], [1, 'W', 3], [1, 'E', 3], [2, 'E', 3], [2, 'E', 1], [2, 'E', 2], [13, 'E', 1], [1, 'W', 1], [1, 'E', 1]], 'toll_dir': 'E', 'base': 600, 'threshold': 4, 'discount_pct': 25, 'carpool_min': 2}, 2400), ({'trips': [[13, 'E', 1], [1, 'E', 3], [1, 'W', 1], [1, 'W', 3], [1, 'E', 3], [1, 'E', 1], [2, 'E', 2], [1, 'E', 3], [13, 'W', 1], [13, 'W', 3]], 'toll_dir': 'W', 'base': 600, 'threshold': 4, 'discount_pct': 33, 'carpool_min': 2}, 1200), ({'trips': [[2, 'W', 4], [1, 'E', 1], [1, 'E', 1], [13, 'E', 1]], 'toll_dir': 'W', 'base': 725, 'threshold': 5, 'discount_pct': 33, 'carpool_min': 3}, 0)]]
for i, (args, expected) in enumerate(fixtures[N-1]):
    check('fee oracle' + ' %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
fee oracle 0	`0`	`0`	Passed
fee oracle 1	`2550`	`1200`	Failed
fee oracle 2	`850`	`850`	Passed
fee oracle 3	`2610`	`2610`	Passed
fee oracle 4	`1800`	`1200`	Failed
fee oracle 5	`4350`	`2700`	Failed
fee oracle 6	`3145`	`2660`	Failed
fee oracle 7	`1450`	`1450`	Passed

SHA-256 / 93ce345ee84c1af0700f3d1cf7a4fbe907e2a021043dbf4d1a8e5242557f7523

2 / The unsuccessful fix

Exit 1

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

N = 1
observations = []
def solve(x):
    counts = {}
    total = 0
    for month, d, occ in x['trips']:
        if d != x['toll_dir']:
            continue
        if occ >= 3:
            continue
        k = counts.get(month, 0) + 1
        counts[month] = k
        if k > x['threshold']:
            total += x['base'] * (100 - x['discount_pct']) // 100
        else:
            total += x['base']
    return total
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[({'trips': [[2, 'E', 1], [1, 'E', 4], [1, 'E', 1]], 'toll_dir': 'W', 'base': 850, 'threshold': 4, 'discount_pct': 40, 'carpool_min': 2}, 0), ({'trips': [[2, 'W', 1], [13, 'E', 2], [13, 'E', 1], [1, 'E', 2], [1, 'W', 3], [1, 'E', 1], [1, 'E', 3], [1, 'W', 2], [13, 'E', 2], [2, 'W', 1], [1, 'E', 4], [1, 'W', 1], [2, 'W', 1], [2, 'E', 3]], 'toll_dir': 'E', 'base': 600, 'threshold': 1, 'discount_pct': 25, 'carpool_min': 2}, 1200), ({'trips': [[1, 'E', 4], [1, 'W', 2], [1, 'E', 3], [2, 'E', 3], [1, 'W', 2], [1, 'E', 4], [13, 'W', 1], [1, 'W', 4], [1, 'E', 1]], 'toll_dir': 'E', 'base': 850, 'threshold': 1, 'discount_pct': 40, 'carpool_min': 2}, 850), ({'trips': [[2, 'W', 1], [1, 'W', 1], [1, 'E', 1], [1, 'E', 1], [1, 'E', 1], [1, 'W', 2], [1, 'W', 2]], 'toll_dir': 'W', 'base': 725, 'threshold': 2, 'discount_pct': 40, 'carpool_min': 3}, 2610), ({'trips': [[1, 'W', 1], [1, 'W', 3], [2, 'E', 1], [1, 'E', 4], [1, 'E', 3], [2, 'E', 4], [1, 'E', 4], [1, 'E', 4], [13, 'E', 3], [1, 'W', 1], [2, 'E', 3]], 'toll_dir': 'W', 'base': 600, 'threshold': 3, 'discount_pct': 40, 'carpool_min': 3}, 1200), ({'trips': [[13, 'W', 1], [1, 'E', 3], [1, 'E', 2], [13, 'W', 2], [1, 'E', 3], [13, 'W', 1], [13, 'W', 1], [13, 'W', 1], [1, 'W', 1], [2, 'W', 2], [1, 'E', 1], [13, 'E', 3], [1, 'W', 2]], 'toll_dir': 'W', 'base': 600, 'threshold': 2, 'discount_pct': 25, 'carpool_min': 2}, 2700), ({'trips': [[1, 'W', 1], [1, 'W', 1], [1, 'W', 3], [1, 'W', 1], [13, 'W', 1]], 'toll_dir': 'W', 'base': 725, 'threshold': 2, 'discount_pct': 33, 'carpool_min': 3}, 2660), ({'trips': [[13, 'W', 1], [13, 'E', 1], [1, 'E', 1], [1, 'W', 1], [13, 'W', 3], [2, 'E', 1]], 'toll_dir': 'W', 'base': 725, 'threshold': 3, 'discount_pct': 40, 'carpool_min': 2}, 1450)], [({'trips': [[1, 'W', 1], [1, 'W', 1], [1, 'W', 3], [1, 'W', 1], [13, 'W', 1]], 'toll_dir': 'W', 'base': 725, 'threshold': 2, 'discount_pct': 33, 'carpool_min': 3}, 2660), ({'trips': [[13, 'W', 2], [13, 'E', 4], [13, 'E', 4], [13, 'E', 2], [13, 'E', 1]], 'toll_dir': 'W', 'base': 850, 'threshold': 5, 'discount_pct': 40, 'carpool_min': 3}, 850), ({'trips': [[1, 'E', 1], [1, 'E', 1], [2, 'W', 3]], 'toll_dir': 'E', 'base': 850, 'threshold': 1, 'discount_pct': 25, 'carpool_min': 2}, 1487), ({'trips': [[13, 'W', 2], [13, 'W', 1], [13, 'W', 1], [13, 'W', 4], [1, 'W', 1]], 'toll_dir': 'E', 'base': 600, 'threshold': 4, 'discount_pct': 33, 'carpool_min': 2}, 0), ({'trips': [[1, 'E', 1], [1, 'W', 1], [1, 'E', 1], [2, 'E', 2], [2, 'W', 2], [1, 'W', 1]], 'toll_dir': 'W', 'base': 600, 'threshold': 1, 'discount_pct': 33, 'carpool_min': 2}, 1002), ({'trips': [[13, 'W', 2], [1, 'E', 2], [2, 'W', 1], [13, 'W', 4], [1, 'E', 3], [1, 'W', 3], [1, 'E', 1], [2, 'E', 2]], 'toll_dir': 'W', 'base': 850, 'threshold': 1, 'discount_pct': 33, 'carpool_min': 2}, 850), ({'trips': [[13, 'W', 1], [1, 'E', 2], [13, 'W', 1], [1, 'W', 1], [1, 'E', 1], [1, 'E', 2], [1, 'E', 3], [2, 'E', 1], [1, 'W', 2], [1, 'W', 1], [1, 'E', 1], [2, 'W', 1], [1, 'W', 1], [2, 'E', 1], [1, 'E', 3], [1, 'E', 2]], 'toll_dir': 'W', 'base': 850, 'threshold': 3, 'discount_pct': 40, 'carpool_min': 3}, 5610), ({'trips': [[1, 'W', 2], [1, 'W', 1], [13, 'W', 1], [2, 'W', 1]], 'toll_dir': 'E', 'base': 725, 'threshold': 2, 'discount_pct': 40, 'carpool_min': 2}, 0)], [({'trips': [[1, 'W', 1], [1, 'W', 1], [1, 'W', 3], [1, 'W', 1], [13, 'W', 1]], 'toll_dir': 'W', 'base': 725, 'threshold': 2, 'discount_pct': 33, 'carpool_min': 3}, 2660), ({'trips': [[1, 'W', 1], [2, 'W', 4], [1, 'E', 3], [1, 'E', 3], [1, 'W', 1], [13, 'E', 1], [1, 'E', 4], [2, 'E', 1], [1, 'W', 2], [2, 'E', 1], [2, 'E', 3]], 'toll_dir': 'E', 'base': 850, 'threshold': 3, 'discount_pct': 25, 'carpool_min': 2}, 2550), ({'trips': [[13, 'E', 1], [1, 'W', 1], [13, 'E', 2], [1, 'E', 1], [1, 'W', 1], [1, 'W', 2], [1, 'W', 4], [1, 'W', 1], [2, 'W', 1]], 'toll_dir': 'E', 'base': 600, 'threshold': 1, 'discount_pct': 25, 'carpool_min': 3}, 1650), ({'trips': [[1, 'W', 2], [1, 'W', 4], [1, 'E', 1], [13, 'E', 1], [1, 'E', 1], [2, 'E', 1], [2, 'W', 1], [2, 'W', 1], [2, 'E', 1]], 'toll_dir': 'W', 'base': 850, 'threshold': 5, 'discount_pct': 40, 'carpool_min': 2}, 1700), ({'trips': [[13, 'E', 1], [13, 'E', 2], [1, 'W', 2], [1, 'E', 3], [2, 'W', 4], [1, 'W', 2]], 'toll_dir': 'W', 'base': 725, 'threshold': 4, 'discount_pct': 40, 'carpool_min': 2}, 0), ({'trips': [[13, 'E', 3], [1, 'E', 3], [1, 'E', 3], [1, 'E', 1], [1, 'E', 1], [1, 'W', 4]], 'toll_dir': 'W', 'base': 600, 'threshold': 5, 'discount_pct': 25, 'carpool_min': 2}, 0), ({'trips': [[1, 'E', 2], [1, 'W', 1], [1, 'W', 1], [1, 'W', 1], [13, 'W', 3], [13, 'E', 4], [1, 'W', 3], [1, 'E', 3], [1, 'E', 1], [1, 'W', 1], [1, 'E', 3]], 'toll_dir': 'W', 'base': 725, 'threshold': 3, 'discount_pct': 25, 'carpool_min': 2}, 2718), ({'trips': [[2, 'E', 3], [2, 'W', 1], [1, 'E', 2], [1, 'E', 2], [2, 'W', 1], [1, 'E', 1]], 'toll_dir': 'W', 'base': 850, 'threshold': 3, 'discount_pct': 33, 'carpool_min': 2}, 1700)], [({'trips': [[1, 'W', 1], [1, 'W', 1], [1, 'W', 3], [1, 'W', 1], [13, 'W', 1]], 'toll_dir': 'W', 'base': 725, 'threshold': 2, 'discount_pct': 33, 'carpool_min': 3}, 2660), ({'trips': [[13, 'E', 3], [1, 'E', 1], [1, 'W', 1], [2, 'E', 1], [1, 'E', 1], [13, 'W', 1], [13, 'E', 1], [13, 'E', 3]], 'toll_dir': 'W', 'base': 850, 'threshold': 2, 'discount_pct': 25, 'carpool_min': 3}, 1700), ({'trips': [[2, 'E', 2], [2, 'E', 4], [13, 'E', 2], [1, 'W', 2], [2, 'W', 3], [2, 'E', 1], [2, 'W', 1], [2, 'E', 1], [2, 'E', 2], [1, 'W', 2], [13, 'W', 1]], 'toll_dir': 'E', 'base': 600, 'threshold': 3, 'discount_pct': 40, 'carpool_min': 3}, 2760), ({'trips': [[13, 'W', 1], [2, 'W', 1], [1, 'W', 2], [1, 'W', 1], [13, 'W', 1], [1, 'E', 1], [1, 'W', 1], [1, 'W', 4], [1, 'W', 1], [2, 'E', 1]], 'toll_dir': 'E', 'base': 725, 'threshold': 1, 'discount_pct': 25, 'carpool_min': 2}, 1450), ({'trips': [[1, 'E', 1], [13, 'W', 1], [1, 'E', 2], [1, 'W', 3], [1, 'W', 1], [2, 'W', 3], [1, 'E', 1], [1, 'E', 1], [2, 'E', 2]], 'toll_dir': 'E', 'base': 725, 'threshold': 3, 'discount_pct': 33, 'carpool_min': 2}, 2175), ({'trips': [[1, 'E', 1], [2, 'W', 2], [2, 'E', 1], [2, 'W', 1], [1, 'E', 2], [13, 'E', 1], [1, 'W', 2], [1, 'W', 1]], 'toll_dir': 'E', 'base': 600, 'threshold': 5, 'discount_pct': 40, 'carpool_min': 3}, 2400), ({'trips': [[1, 'E', 1], [13, 'E', 4], [2, 'E', 1], [13, 'W', 4], [1, 'W', 1], [1, 'W', 1]], 'toll_dir': 'W', 'base': 850, 'threshold': 1, 'discount_pct': 40, 'carpool_min': 3}, 1360), ({'trips': [[13, 'E', 4], [1, 'E', 4], [1, 'W', 1], [1, 'W', 1], [1, 'E', 1], [1, 'W', 2], [13, 'E', 1], [1, 'E', 3], [1, 'W', 3], [1, 'W', 2], [13, 'E', 1]], 'toll_dir': 'W', 'base': 600, 'threshold': 5, 'discount_pct': 40, 'carpool_min': 2}, 1200)], [({'trips': [[13, 'E', 4], [13, 'W', 1], [1, 'W', 1], [1, 'E', 1]], 'toll_dir': 'W', 'base': 725, 'threshold': 2, 'discount_pct': 25, 'carpool_min': 3}, 1450), ({'trips': [[1, 'W', 1], [13, 'E', 1], [1, 'E', 1], [2, 'W', 1], [1, 'E', 1], [1, 'E', 2], [2, 'E', 2], [1, 'W', 1], [1, 'E', 2]], 'toll_dir': 'E', 'base': 600, 'threshold': 2, 'discount_pct': 40, 'carpool_min': 2}, 1800), ({'trips': [[2, 'E', 4], [2, 'W', 1], [2, 'E', 1], [1, 'E', 3], [1, 'W', 2], [13, 'W', 1], [2, 'W', 4], [1, 'E', 1], [1, 'E', 1], [2, 'W', 1], [13, 'W', 2], [1, 'E', 2], [2, 'E', 2], [1, 'W', 1], [1, 'W', 3]], 'toll_dir': 'E', 'base': 725, 'threshold': 2, 'discount_pct': 40, 'carpool_min': 3}, 3335), ({'trips': [[1, 'E', 2], [2, 'W', 3], [1, 'W', 1], [2, 'E', 3], [13, 'E', 1], [1, 'E', 3], [1, 'W', 2], [1, 'W', 1], [1, 'E', 3], [1, 'W', 3], [13, 'E', 1], [13, 'E', 3], [1, 'W', 1], [1, 'W', 1], [1, 'W', 4]], 'toll_dir': 'W', 'base': 600, 'threshold': 1, 'discount_pct': 40, 'carpool_min': 3}, 2040), ({'trips': [[1, 'W', 1], [1, 'W', 1], [1, 'W', 3], [1, 'W', 1], [13, 'W', 1]], 'toll_dir': 'W', 'base': 725, 'threshold': 2, 'discount_pct': 33, 'carpool_min': 3}, 2660), ({'trips': [[1, 'E', 2], [1, 'W', 1], [1, 'E', 3], [2, 'W', 2], [1, 'W', 1], [1, 'E', 1], [2, 'W', 4], [1, 'W', 3], [1, 'E', 3], [2, 'E', 3], [2, 'E', 1], [2, 'E', 2], [13, 'E', 1], [1, 'W', 1], [1, 'E', 1]], 'toll_dir': 'E', 'base': 600, 'threshold': 4, 'discount_pct': 25, 'carpool_min': 2}, 2400), ({'trips': [[13, 'E', 1], [1, 'E', 3], [1, 'W', 1], [1, 'W', 3], [1, 'E', 3], [1, 'E', 1], [2, 'E', 2], [1, 'E', 3], [13, 'W', 1], [13, 'W', 3]], 'toll_dir': 'W', 'base': 600, 'threshold': 4, 'discount_pct': 33, 'carpool_min': 2}, 1200), ({'trips': [[2, 'W', 4], [1, 'E', 1], [1, 'E', 1], [13, 'E', 1]], 'toll_dir': 'W', 'base': 725, 'threshold': 5, 'discount_pct': 33, 'carpool_min': 3}, 0)]]
for i, (args, expected) in enumerate(fixtures[N-1]):
    check('fee oracle' + ' %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
fee oracle 0	`0`	`0`	Passed
fee oracle 1	`2550`	`1200`	Failed
fee oracle 2	`850`	`850`	Passed
fee oracle 3	`2610`	`2610`	Passed
fee oracle 4	`1200`	`1200`	Passed
fee oracle 5	`4350`	`2700`	Failed
fee oracle 6	`2660`	`2660`	Passed
fee oracle 7	`1450`	`1450`	Passed

SHA-256 / 253b65447f3c93b916dd1b337ef6e0af692fb9a25ecbc47553aa252172601dae

3 / The verified repair

Exit 0

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

N = 1
observations = []
def solve(x):
    counts = {}
    total = 0
    for month, d, occ in x['trips']:
        if d != x['toll_dir']:
            continue
        if occ >= x['carpool_min']:
            continue
        k = counts.get(month, 0) + 1
        counts[month] = k
        if k > x['threshold']:
            total += x['base'] * (100 - x['discount_pct']) // 100
        else:
            total += x['base']
    return total
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[({'trips': [[2, 'E', 1], [1, 'E', 4], [1, 'E', 1]], 'toll_dir': 'W', 'base': 850, 'threshold': 4, 'discount_pct': 40, 'carpool_min': 2}, 0), ({'trips': [[2, 'W', 1], [13, 'E', 2], [13, 'E', 1], [1, 'E', 2], [1, 'W', 3], [1, 'E', 1], [1, 'E', 3], [1, 'W', 2], [13, 'E', 2], [2, 'W', 1], [1, 'E', 4], [1, 'W', 1], [2, 'W', 1], [2, 'E', 3]], 'toll_dir': 'E', 'base': 600, 'threshold': 1, 'discount_pct': 25, 'carpool_min': 2}, 1200), ({'trips': [[1, 'E', 4], [1, 'W', 2], [1, 'E', 3], [2, 'E', 3], [1, 'W', 2], [1, 'E', 4], [13, 'W', 1], [1, 'W', 4], [1, 'E', 1]], 'toll_dir': 'E', 'base': 850, 'threshold': 1, 'discount_pct': 40, 'carpool_min': 2}, 850), ({'trips': [[2, 'W', 1], [1, 'W', 1], [1, 'E', 1], [1, 'E', 1], [1, 'E', 1], [1, 'W', 2], [1, 'W', 2]], 'toll_dir': 'W', 'base': 725, 'threshold': 2, 'discount_pct': 40, 'carpool_min': 3}, 2610), ({'trips': [[1, 'W', 1], [1, 'W', 3], [2, 'E', 1], [1, 'E', 4], [1, 'E', 3], [2, 'E', 4], [1, 'E', 4], [1, 'E', 4], [13, 'E', 3], [1, 'W', 1], [2, 'E', 3]], 'toll_dir': 'W', 'base': 600, 'threshold': 3, 'discount_pct': 40, 'carpool_min': 3}, 1200), ({'trips': [[13, 'W', 1], [1, 'E', 3], [1, 'E', 2], [13, 'W', 2], [1, 'E', 3], [13, 'W', 1], [13, 'W', 1], [13, 'W', 1], [1, 'W', 1], [2, 'W', 2], [1, 'E', 1], [13, 'E', 3], [1, 'W', 2]], 'toll_dir': 'W', 'base': 600, 'threshold': 2, 'discount_pct': 25, 'carpool_min': 2}, 2700), ({'trips': [[1, 'W', 1], [1, 'W', 1], [1, 'W', 3], [1, 'W', 1], [13, 'W', 1]], 'toll_dir': 'W', 'base': 725, 'threshold': 2, 'discount_pct': 33, 'carpool_min': 3}, 2660), ({'trips': [[13, 'W', 1], [13, 'E', 1], [1, 'E', 1], [1, 'W', 1], [13, 'W', 3], [2, 'E', 1]], 'toll_dir': 'W', 'base': 725, 'threshold': 3, 'discount_pct': 40, 'carpool_min': 2}, 1450)], [({'trips': [[1, 'W', 1], [1, 'W', 1], [1, 'W', 3], [1, 'W', 1], [13, 'W', 1]], 'toll_dir': 'W', 'base': 725, 'threshold': 2, 'discount_pct': 33, 'carpool_min': 3}, 2660), ({'trips': [[13, 'W', 2], [13, 'E', 4], [13, 'E', 4], [13, 'E', 2], [13, 'E', 1]], 'toll_dir': 'W', 'base': 850, 'threshold': 5, 'discount_pct': 40, 'carpool_min': 3}, 850), ({'trips': [[1, 'E', 1], [1, 'E', 1], [2, 'W', 3]], 'toll_dir': 'E', 'base': 850, 'threshold': 1, 'discount_pct': 25, 'carpool_min': 2}, 1487), ({'trips': [[13, 'W', 2], [13, 'W', 1], [13, 'W', 1], [13, 'W', 4], [1, 'W', 1]], 'toll_dir': 'E', 'base': 600, 'threshold': 4, 'discount_pct': 33, 'carpool_min': 2}, 0), ({'trips': [[1, 'E', 1], [1, 'W', 1], [1, 'E', 1], [2, 'E', 2], [2, 'W', 2], [1, 'W', 1]], 'toll_dir': 'W', 'base': 600, 'threshold': 1, 'discount_pct': 33, 'carpool_min': 2}, 1002), ({'trips': [[13, 'W', 2], [1, 'E', 2], [2, 'W', 1], [13, 'W', 4], [1, 'E', 3], [1, 'W', 3], [1, 'E', 1], [2, 'E', 2]], 'toll_dir': 'W', 'base': 850, 'threshold': 1, 'discount_pct': 33, 'carpool_min': 2}, 850), ({'trips': [[13, 'W', 1], [1, 'E', 2], [13, 'W', 1], [1, 'W', 1], [1, 'E', 1], [1, 'E', 2], [1, 'E', 3], [2, 'E', 1], [1, 'W', 2], [1, 'W', 1], [1, 'E', 1], [2, 'W', 1], [1, 'W', 1], [2, 'E', 1], [1, 'E', 3], [1, 'E', 2]], 'toll_dir': 'W', 'base': 850, 'threshold': 3, 'discount_pct': 40, 'carpool_min': 3}, 5610), ({'trips': [[1, 'W', 2], [1, 'W', 1], [13, 'W', 1], [2, 'W', 1]], 'toll_dir': 'E', 'base': 725, 'threshold': 2, 'discount_pct': 40, 'carpool_min': 2}, 0)], [({'trips': [[1, 'W', 1], [1, 'W', 1], [1, 'W', 3], [1, 'W', 1], [13, 'W', 1]], 'toll_dir': 'W', 'base': 725, 'threshold': 2, 'discount_pct': 33, 'carpool_min': 3}, 2660), ({'trips': [[1, 'W', 1], [2, 'W', 4], [1, 'E', 3], [1, 'E', 3], [1, 'W', 1], [13, 'E', 1], [1, 'E', 4], [2, 'E', 1], [1, 'W', 2], [2, 'E', 1], [2, 'E', 3]], 'toll_dir': 'E', 'base': 850, 'threshold': 3, 'discount_pct': 25, 'carpool_min': 2}, 2550), ({'trips': [[13, 'E', 1], [1, 'W', 1], [13, 'E', 2], [1, 'E', 1], [1, 'W', 1], [1, 'W', 2], [1, 'W', 4], [1, 'W', 1], [2, 'W', 1]], 'toll_dir': 'E', 'base': 600, 'threshold': 1, 'discount_pct': 25, 'carpool_min': 3}, 1650), ({'trips': [[1, 'W', 2], [1, 'W', 4], [1, 'E', 1], [13, 'E', 1], [1, 'E', 1], [2, 'E', 1], [2, 'W', 1], [2, 'W', 1], [2, 'E', 1]], 'toll_dir': 'W', 'base': 850, 'threshold': 5, 'discount_pct': 40, 'carpool_min': 2}, 1700), ({'trips': [[13, 'E', 1], [13, 'E', 2], [1, 'W', 2], [1, 'E', 3], [2, 'W', 4], [1, 'W', 2]], 'toll_dir': 'W', 'base': 725, 'threshold': 4, 'discount_pct': 40, 'carpool_min': 2}, 0), ({'trips': [[13, 'E', 3], [1, 'E', 3], [1, 'E', 3], [1, 'E', 1], [1, 'E', 1], [1, 'W', 4]], 'toll_dir': 'W', 'base': 600, 'threshold': 5, 'discount_pct': 25, 'carpool_min': 2}, 0), ({'trips': [[1, 'E', 2], [1, 'W', 1], [1, 'W', 1], [1, 'W', 1], [13, 'W', 3], [13, 'E', 4], [1, 'W', 3], [1, 'E', 3], [1, 'E', 1], [1, 'W', 1], [1, 'E', 3]], 'toll_dir': 'W', 'base': 725, 'threshold': 3, 'discount_pct': 25, 'carpool_min': 2}, 2718), ({'trips': [[2, 'E', 3], [2, 'W', 1], [1, 'E', 2], [1, 'E', 2], [2, 'W', 1], [1, 'E', 1]], 'toll_dir': 'W', 'base': 850, 'threshold': 3, 'discount_pct': 33, 'carpool_min': 2}, 1700)], [({'trips': [[1, 'W', 1], [1, 'W', 1], [1, 'W', 3], [1, 'W', 1], [13, 'W', 1]], 'toll_dir': 'W', 'base': 725, 'threshold': 2, 'discount_pct': 33, 'carpool_min': 3}, 2660), ({'trips': [[13, 'E', 3], [1, 'E', 1], [1, 'W', 1], [2, 'E', 1], [1, 'E', 1], [13, 'W', 1], [13, 'E', 1], [13, 'E', 3]], 'toll_dir': 'W', 'base': 850, 'threshold': 2, 'discount_pct': 25, 'carpool_min': 3}, 1700), ({'trips': [[2, 'E', 2], [2, 'E', 4], [13, 'E', 2], [1, 'W', 2], [2, 'W', 3], [2, 'E', 1], [2, 'W', 1], [2, 'E', 1], [2, 'E', 2], [1, 'W', 2], [13, 'W', 1]], 'toll_dir': 'E', 'base': 600, 'threshold': 3, 'discount_pct': 40, 'carpool_min': 3}, 2760), ({'trips': [[13, 'W', 1], [2, 'W', 1], [1, 'W', 2], [1, 'W', 1], [13, 'W', 1], [1, 'E', 1], [1, 'W', 1], [1, 'W', 4], [1, 'W', 1], [2, 'E', 1]], 'toll_dir': 'E', 'base': 725, 'threshold': 1, 'discount_pct': 25, 'carpool_min': 2}, 1450), ({'trips': [[1, 'E', 1], [13, 'W', 1], [1, 'E', 2], [1, 'W', 3], [1, 'W', 1], [2, 'W', 3], [1, 'E', 1], [1, 'E', 1], [2, 'E', 2]], 'toll_dir': 'E', 'base': 725, 'threshold': 3, 'discount_pct': 33, 'carpool_min': 2}, 2175), ({'trips': [[1, 'E', 1], [2, 'W', 2], [2, 'E', 1], [2, 'W', 1], [1, 'E', 2], [13, 'E', 1], [1, 'W', 2], [1, 'W', 1]], 'toll_dir': 'E', 'base': 600, 'threshold': 5, 'discount_pct': 40, 'carpool_min': 3}, 2400), ({'trips': [[1, 'E', 1], [13, 'E', 4], [2, 'E', 1], [13, 'W', 4], [1, 'W', 1], [1, 'W', 1]], 'toll_dir': 'W', 'base': 850, 'threshold': 1, 'discount_pct': 40, 'carpool_min': 3}, 1360), ({'trips': [[13, 'E', 4], [1, 'E', 4], [1, 'W', 1], [1, 'W', 1], [1, 'E', 1], [1, 'W', 2], [13, 'E', 1], [1, 'E', 3], [1, 'W', 3], [1, 'W', 2], [13, 'E', 1]], 'toll_dir': 'W', 'base': 600, 'threshold': 5, 'discount_pct': 40, 'carpool_min': 2}, 1200)], [({'trips': [[13, 'E', 4], [13, 'W', 1], [1, 'W', 1], [1, 'E', 1]], 'toll_dir': 'W', 'base': 725, 'threshold': 2, 'discount_pct': 25, 'carpool_min': 3}, 1450), ({'trips': [[1, 'W', 1], [13, 'E', 1], [1, 'E', 1], [2, 'W', 1], [1, 'E', 1], [1, 'E', 2], [2, 'E', 2], [1, 'W', 1], [1, 'E', 2]], 'toll_dir': 'E', 'base': 600, 'threshold': 2, 'discount_pct': 40, 'carpool_min': 2}, 1800), ({'trips': [[2, 'E', 4], [2, 'W', 1], [2, 'E', 1], [1, 'E', 3], [1, 'W', 2], [13, 'W', 1], [2, 'W', 4], [1, 'E', 1], [1, 'E', 1], [2, 'W', 1], [13, 'W', 2], [1, 'E', 2], [2, 'E', 2], [1, 'W', 1], [1, 'W', 3]], 'toll_dir': 'E', 'base': 725, 'threshold': 2, 'discount_pct': 40, 'carpool_min': 3}, 3335), ({'trips': [[1, 'E', 2], [2, 'W', 3], [1, 'W', 1], [2, 'E', 3], [13, 'E', 1], [1, 'E', 3], [1, 'W', 2], [1, 'W', 1], [1, 'E', 3], [1, 'W', 3], [13, 'E', 1], [13, 'E', 3], [1, 'W', 1], [1, 'W', 1], [1, 'W', 4]], 'toll_dir': 'W', 'base': 600, 'threshold': 1, 'discount_pct': 40, 'carpool_min': 3}, 2040), ({'trips': [[1, 'W', 1], [1, 'W', 1], [1, 'W', 3], [1, 'W', 1], [13, 'W', 1]], 'toll_dir': 'W', 'base': 725, 'threshold': 2, 'discount_pct': 33, 'carpool_min': 3}, 2660), ({'trips': [[1, 'E', 2], [1, 'W', 1], [1, 'E', 3], [2, 'W', 2], [1, 'W', 1], [1, 'E', 1], [2, 'W', 4], [1, 'W', 3], [1, 'E', 3], [2, 'E', 3], [2, 'E', 1], [2, 'E', 2], [13, 'E', 1], [1, 'W', 1], [1, 'E', 1]], 'toll_dir': 'E', 'base': 600, 'threshold': 4, 'discount_pct': 25, 'carpool_min': 2}, 2400), ({'trips': [[13, 'E', 1], [1, 'E', 3], [1, 'W', 1], [1, 'W', 3], [1, 'E', 3], [1, 'E', 1], [2, 'E', 2], [1, 'E', 3], [13, 'W', 1], [13, 'W', 3]], 'toll_dir': 'W', 'base': 600, 'threshold': 4, 'discount_pct': 33, 'carpool_min': 2}, 1200), ({'trips': [[2, 'W', 4], [1, 'E', 1], [1, 'E', 1], [13, 'E', 1]], 'toll_dir': 'W', 'base': 725, 'threshold': 5, 'discount_pct': 33, 'carpool_min': 3}, 0)]]
for i, (args, expected) in enumerate(fixtures[N-1]):
    check('fee oracle' + ' %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
fee oracle 0	`0`	`0`	Passed
fee oracle 1	`1200`	`1200`	Passed
fee oracle 2	`850`	`850`	Passed
fee oracle 3	`2610`	`2610`	Passed
fee oracle 4	`1200`	`1200`	Passed
fee oracle 5	`2700`	`2700`	Passed
fee oracle 6	`2660`	`2660`	Passed
fee oracle 7	`1450`	`1450`	Passed

SHA-256 / 9bd71e8623b224f340db9a8cc0999f72b40511eeb988f47d7025f9d5a00aa55b

Verification & scope

A deterministic, bounded toy model with a stipulated contract; it makes no claim of conformance to any agency manual or 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.

Observations recorded using Python 3.12.14 at 2026-09-29T14:48:04.186675+00:00.

Case digest / cd5e11a9f2b66cd578ad064878f3f91363602c1a9e22298ff3aac30fecc5a9b2