Cart with nested transactionsCodingImplement a cart whose updates run inside nestable transactions that commit or roll back as a unit. Reported on 1point3acres' Decagon bank; reconstructed in our own words.
Last asked Jul 2026
#transactions
Transactional in-memory key-value databaseCodingBuild an in-memory key-value store with transactional reads and writes: operations inside a transaction see each other's effects and commit or roll back atomically. Reported on…Last asked Jul 2026
Bank ledger with two-step transfers and mergesCodingModel simple bank accounts with deposits and withdrawals, a transfer flow that holds funds until the recipient accepts, and an account-merge step that must keep working even if a…Last asked Jun 2026
+3Key-value store with nested transaction rollbackCodingImplement an in-memory key-value store whose string keys map to string values. It supports transactions, and transactions can be nested. Implement the class KeyValueStore: -…Last asked May 2026
Design a digital game store backendSystem designDesign the backend of an online store that sells digital games: players browse a catalog, buy games, and own them afterwards. Focus on the purchase: taking the payment, granting…Last asked Dec 2025
Explain ACID and transaction isolation levelsSystem designExplain what each letter of ACID guarantees, then walk through the standard isolation levels (read uncommitted, read committed, repeatable read, serializable) and the anomalies…Last asked Dec 2025