Build a Progressive Banking System

Question

Design and implement a progressive banking system that can handle various banking operations like deposits, withdrawals, and balance inquiries.

Codemia · Accepted Answer

To build a progressive banking system, we need to support the following operations:
1. **Deposit**: Add funds to an account.
2. **Withdraw**: Remove funds from an account, ensuring sufficient balance.
3. **Balance Inquiry**: Check the current balance of an account.
4. **Account Creation**: Allow users to create new accounts with unique identifiers.

We can design the banking system using an object-oriented approach. We will create a `BankAccount` class that encapsulates the account's properties and methods. The key attributes will include:
- `account_id`: Unique identifier for the account.
- `balance`: Current balance of the account.

The methods will include:
- `deposit(amount)`: Adds the specified amount to the balance.
- `withdraw(amount)`: Deducts the specified amount from the balance, with checks for sufficient funds.
- `get_balance()`: Returns the current balance.

Here is a simple implementation in Python:
```python
class BankAccount:
    def __init__(self, account_id):
        self.account_id = account_id
        self.balance = 0.0

def deposit(self, amount):
        if amount <= 0:
            raise ValueError('Deposit amount must be positive')
        self.balance += amount

def withdraw(self, amount):
        if amount <= 0:
            raise ValueError('Withdrawal amount must be positive')
        if amount > self.balance:
            raise ValueError('Insufficient funds')
        self.balance -= amount

def get_balance(self):
        return self.balance
```
This code defines the `BankAccount` class and implements the required methods.

The time complexity for each operation (deposit, withdraw, get_balance) is O(1), as they involve simple arithmetic and attribute access. The space complexity is also O(1) since we are using a fixed amount of space for storing account details regardless of the number of transactions.

We should consider edge cases such as:
- Depositing or withdrawing negative amounts, which should raise exceptions.
- Attempting to withdraw more than the available balance, which should also raise an exception.

In a real-world scenario, we could discuss adding features like transaction histories, interest calculations, or even multi-threading to handle concurrent transactions. These features would increase complexity but provide a more robust banking system.

Build a Progressive Banking System

Instacart

What the Interviewer Expects

Key Topics to Cover

How to Approach This

Possible Follow-up Questions

Sharpen Your Skills on Codemia

Sample Answer

Requirements

High-Level Design

Submit Your Answer

Instacart Software Engineer Interview Guide

Related Questions

Binary Search on graph

Count kth largest element in array

Find connected components in string

Merge Three Sorted strings

Binary Search on string