Banking System With Transfers

MediumPython

Problem

Implement an in-memory account processor for Circle USDC accounts. Process account creation, deposits, and transfers while ensuring invalid transfers are atomic and repeated operation IDs are idempotent.

Each operation has a unique operation_id. If the same ID is submitted again with the exact same operation data, return the original result without applying it again. If an existing ID is reused with different data, reject the operation.

Formal Specification

Implement process_operations(operations). operations is a list of arrays in one of these forms:

[operation_id, "CREATE", account_id]
[operation_id, "DEPOSIT", account_id, amount]
[operation_id, "TRANSFER", source_id, destination_id, amount]

Return an object with results, a Boolean result for each input operation, and balances, the final account balances. Account IDs and operation IDs are strings. All amounts are positive integers. New accounts start with balance 0.

A transfer succeeds only when both accounts exist, the accounts differ, and the source has enough funds. Failed operations must not modify any balance.

Constraints

1 <= operations.length <= 2 * 10^5
Each operation has a unique ID unless it is an intentional retry
Account IDs and operation IDs are nonempty strings of at most 32 alphanumeric characters
Amounts are positive integers at most 10^9
Balances are nonnegative and fit in Python integers

Function Signature

def process_operations(operations):

Formal Specification

Implement process_operations(operations). operations is a list of arrays in one of these forms:

[operation_id, "CREATE", account_id]
[operation_id, "DEPOSIT", account_id, amount]
[operation_id, "TRANSFER", source_id, destination_id, amount]

A transfer succeeds only when both accounts exist, the accounts differ, and the source has enough funds. Failed operations must not modify any balance.