Design An Atm Machine - Leetcode Solution

The Design an ATM Machine problem on LeetCode requires a system design approach to solve. The prompt of the problem is to design an ATM machine that has the following functionalities:

1. It should be able to dispense cash in multiples of $10.
2. It should have a secure login system for user authentication.
3. It should be able to check the account balance of the user.
4. It should be able to withdraw money from the user's account.

To design an ATM machine, we need to consider the following components:

1. User Interface: The ATM machine should have a user interface to display information to the user and take input from them, such as entering a PIN, selecting an amount to withdraw, or displaying the amount dispensed.

2. Cash Dispenser: The ATM machine should have a cash dispenser that is capable of dispensing cash in multiples of $10.

3. Database: The ATM machine should have a database that stores user account information, including the account balance and transaction history.

4. Authentication Component: The ATM machine should have an authentication component that is responsible for verifying the user's identity.

Now, let's see how we can implement each of these components.

1. User Interface:

The user interface of the ATM machine can be implemented using a touch screen display or a keypad. The user interface should have the following functionalities:

a. Login Screen: A login screen where the user can enter their PIN to authenticate themselves.

b. Account Information Screen: After successful authentication, the user should be able to see their account balance and transaction history.

c. Cash Dispenser Screen: The user should be able to select the amount of cash they want to withdraw, and the amount should be displayed on the screen.

d. Confirmation Screen: After selecting the amount, the user should be presented with a confirmation screen to confirm the withdrawal.

e. Receipt Screen: Once the transaction is complete, the user should be given a receipt indicating the transaction details.

2. Cash Dispenser:

The cash dispenser component is responsible for dispensing cash in multiples of $10. It should have a mechanism to count and keep track of how much money is available.

3. Database:

The database component is responsible for storing account information, including the account balance and transaction history. The database should be secure and accessible only by authorized personnel.

4. Authentication Component:

The authentication component is responsible for verifying the user's identity using their PIN. It should be secure and prevent unauthorized access.

Overall, the ATM machine should be designed in such a way that it provides a seamless and secure user experience. The system should also be scalable and capable of handling multiple users simultaneously.

In conclusion, the Design an ATM Machine problem on LeetCode requires a system design approach. The ATM machine should have a user interface, a cash dispenser, a database, and an authentication component. By implementing these components efficiently, we can design a robust and secure ATM machine that meets the functional requirements of the problem.

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