Build a Trust-Aware BIN Database

Implement process_bin_operations(operations) for an in-memory database of card-number prefixes. A prefix identifies attributes such as card brand and card type. The function returns the result of every lookup operation, in order.

Each operation is one of:

• ("store", prefix, source, trust, brand, card_type)
• ("lookup", card_number)

prefix, source, brand, and card_type are strings. For a store, at least one of brand or card_type is not None; the other may be None. trust is an integer. Every store is a new write, even when its source and values repeat.

For a lookup, resolve brand and card_type independently:

1. Consider every stored prefix that is a prefix of card_number and that supplied the requested field.
2. Prefer the longest matching prefix.
3. Among writes at that prefix, prefer the highest trust.
4. If trust ties, prefer the most recent write.

A write that omits a field must not erase an older value for that field. Return each lookup as (brand, card_type), using None for a field with no matching write.

Constraints

• 1 <= len(operations) <= 200,000
• Prefixes and card numbers contain only decimal digits.
• 1 <= len(prefix) <= 32; len(card_number) <= 64
• source is retained as write metadata; different sources may report the same values.
• Inputs are valid; no format-validation code is required.

Example behavior

If a six-digit prefix supplies a high-trust brand but no type, and a more specific eight-digit prefix supplies only a type, a matching card number combines the six-digit brand with the eight-digit type. A later equal-trust write wins only for the field it supplies.

Candidate clarifications

Confirm field-by-field merging, longest-prefix precedence over trust, tie-breaking, whether duplicate values are allowed, and the required complexity for heavy lookup traffic.

Build a Trust-Aware BIN Database

Implement process_bin_operations using six parallel operation arrays. A store row supplies a nonempty digit prefix, source, signed-32 trust, and at least one nonempty brand or card_type. The empty string is reserved as the omission sentinel and cannot be a stored brand or card type. A lookup row uses keys[i] as the card number. Resolve brand and type independently by longest matching prefix, then highest trust at that prefix, then most recent equal-trust write. Return [brand, card_type] pairs for lookups, using the reserved empty string for a missing field.

Hints

1. Maintain the trusted winner separately for each field and exact prefix.
2. During lookup, search prefix lengths from longest to shortest for each unresolved field.

Approach

For every exact prefix, keep the winning brand write and type write separately. A new nonempty field replaces its winner only with greater trust or equal trust at a later operation. Lookup scans prefixes from most specific to least and stops searching a field as soon as its longest stored winner is found.

• Time complexity: O(p) per store and O(L^2) character copying per lookup in this direct substring implementation, with L at most 64.
• Space complexity: O(w) for field winners and lookup results.