Process Transactions and Compute Balances

Process Transactions and Compute Balances

You are building a simple ledger system for a banking platform. You are given a list of transactions, where each transaction consists of a transaction_id, timestamp, sender_id, receiver_id, and amount.

Rules:

1. All accounts start with a balance of 0.
2. Transactions must be processed in chronological order. If two transactions have the same timestamp, process them by the order in which they appear in the input list.
3. A transaction is only successful if the sender_id has sufficient funds (balance >= amount). If a transaction fails, it is ignored and does not affect any balances.
4. Account IDs can be any string. If a sender_id or receiver_id has never appeared before, treat their starting balance as 0.

Input

transactions: A list of objects/dictionaries with the following fields: id (str), timestamp (int), sender (str), receiver (str), amount (int).

Output

Return a dictionary where keys are account IDs and values are their final balances.

Example

transactions = [
    {"id": "t1", "timestamp": 10, "sender": "A", "receiver": "B", "amount": 50},
    {"id": "t2", "timestamp": 5, "sender": "B", "receiver": "A", "amount": 20},
    {"id": "t3", "timestamp": 15, "sender": "A", "receiver": "B", "amount": 60}
]

# Expected Output:
# {'A': -10, 'B': 10}
# Explanation: 
# 1. t2 (time 5) is processed first: B sends 20 to A. Balances: B=-20, A=20.
# 2. t1 (time 10): A sends 50 to B. A has 20, needs 50. Transaction fails.
# 3. t3 (time 15): A sends 60 to B. A has 20, needs 60. Transaction fails.

Constraints

• amount > 0.
• Number of transactions: 1 to 10^5.
• Timestamps: 1 to 10^9.