Bank Deposit Priority Queue

This is an implementation of multiple requests being sent using timestamps that have withdraws, deposits, and cashback examples
This is useful to showcase how priority queue's can be used in certain situations, such as using timestamps to balance accounts

Setup

balances: list of ints, 1-indexed
requests: list of tuples (action, timestamp, account_id, amount)
For a withdraw request, we need to process a cashback amount of 2% exactly 24 hours from the withdraw
Timestamps are integer timestamps, may overlap

import time

def now():
    return int(time.time())

def process_requests(balances, requests):
    # implement

def run_scenario(scenario_num, balances, requests, expected_balances, expected_results):
    try:
        final_balances, results = process_requests(list(balances), requests)
        balances_ok = final_balances == expected_balances
        results_ok = results == expected_results
        print(f"Scenario {scenario_num}: {'PASS' if balances_ok and results_ok else 'FAIL'}")
        if not balances_ok:
            print(f"  Expected balances: {expected_balances}, got: {final_balances}")
        if not results_ok:
            print(f"  Expected results: {expected_results}, got: {results}")
    except Exception as e:
        print(f"Scenario {scenario_num}: ERROR - {e}")

if __name__ == "__main__":
    t0 = now()

    # 4 Easy/Normal Scenarios
    scenarios = [
        # 1. Simple deposit and withdraw
        (
            [100, 200],
            [("deposit", t0, 1, 50), ("withdraw", t0+1, 1, 100)],
            [50, 200],
            ["OK", "OK"]
        ),
        # 2. Overdraw attempt
        (
            [100],
            [("withdraw", t0, 1, 150)],
            [100],
            ["Overdraw"]
        ),
        # 3. Invalid account
        (
            [100],
            [("deposit", t0, 2, 50)],
            [100],
            ["Invalid account"]
        ),
        # 4. Cashback processed after 24h
        (
            [100],
            [("cashback", t0, 1, 10)],
            [110],
            ["OK"]
        ),

        # 6 Edge Cases
        # 5. Withdraw after cashback arrives
        (
            [100],
            [("cashback", t0, 1, 50), ("withdraw", t0+24*60*60, 1, 150)],
            [0],
            ["OK", "OK"]
        ),
        # 6. Multiple cashbacks, overlapping timestamps
        (
            [100],
            [("cashback", t0, 1, 10), ("cashback", t0+1, 1, 20), ("withdraw", t0+24*60*60+1, 1, 130)],
            [0],
            ["OK", "OK", "OK"]
        ),
        # 7. Withdraw before cashback arrives (should fail)
        (
            [100],
            [("cashback", t0, 1, 50), ("withdraw", t0+1, 1, 150)],
            [100],
            ["OK", "Overdraw"]
        ),
        # 8. Deposit, withdraw, cashback, withdraw after cashback
        (
            [100],
            [("deposit", t0, 1, 50), ("withdraw", t0+1, 1, 100), ("cashback", t0+2, 1, 20), ("withdraw", t0+2+24*60*60, 1, 70)],
            [0],
            ["OK", "OK", "OK", "OK"]
        ),
        # 9. Invalid action
        (
            [100],
            [("invalid", t0, 1, 10)],
            [100],
            ["Invalid action"]
        ),
        # 10. Withdraw, cashback scheduled after all requests (should be ignored)
        (
            [100],
            [("withdraw", t0, 1, 50), ("cashback", t0+1000000, 1, 999)],
            [50],
            ["OK", "OK"]
        ),
    ]

    for i, (balances, requests, expected_balances, expected_results) in enumerate(scenarios, 1):
        run_scenario(i, balances, requests, expected_balances, expected_results)

Setup​

Setup