Full Stack Developer Test

A web app for a popular AI conference (conducted in New York, with attendees from around the world) uses a signup/login page before users can access their dashboard. The signup/login page uses a form for users to input details and submit. The details are then sent to the backend service for processing. All user actions are logged in a log server. Senior Frontend Engineer, Musk, observed patterns in the issues users are facing with the the web app. Here are the two common patterns that Musk observed in the issues that have been occurring for most users:

Which of the following should Musk do to enhance the user experience with the page?

A: Implement validation using JS event listeners on client-side (e.g., on input or change)
B: Utilize HTML5 built-in form validation attributes (e.g., required, pattern)
C: Use server-side validation and refresh the page on form submission
D: Use a serverless function that processes the user’s form details, saves the user’s entries in the database and responds with validation data

A senior front-end engineer is tasked with optimizing the loading speed of a web application. The current bottleneck is the large number of JavaScript files that must be downloaded before the application becomes interactive. The engineer noticed that the browser spends a lot of time parsing and executing the JS code before making the application interactive. Which of the following techniques should the engineer apply to address this issue?

You are working on a large-scale, distributed, and fault-tolerant message processing system designed to handle high throughput and low latency requirements. The system is based on the publish-subscribe pattern and uses multiple brokers to distribute messages across various topics and partitions. In this architecture, both publishers and subscribers are considered clients. The brokers are responsible for replicating messages among themselves to ensure fault tolerance and data durability.

A client reports successfully publishing a message on a specific topic. However, one of the subscribers has not received the message. To investigate the issue, you have gathered detailed logs and system design data, as shown below:

Based on the information provided, which of the following is the most likely reason for the issue?

A: The message was not published on the topic
B: Client C is not subscribed to the correct topic
C: There is a replication lag between brokers B1 and B2
D: Client C is consuming from the wrong broker
E: The message processing system failed to acknowledge the message

A backend service is experiencing intermittent latency spikes while processing incoming requests. The service is deployed in a multi-node environment with a load balancer in front. You suspect that the issue might be related to resource contention. You collect the following performance metrics from the affected nodes during a spike:

Which of the following is the most probable cause of the latency spikes?
A: High memory usage on the affected nodes.
B: Disk I/O bottlenecks on the affected nodes.
C: Insufficient CPU resources on the affected nodes.
D: Uneven distribution of incoming requests by the load balancer.
E: Network latency between the load balancer and the backend nodes.

Consider the following shorthand CSS example:

background: #f7f7f7 url(jolie.jpg) no-repeat scroll 0px 0px;

Which of the following show the individual background properties represented by the shorthand:

Our intern is writing a colorful blog post, and has written the following code. What colors will the sentences be?

A: Sentence 1 will be gray, Sentence 2 will be pink.
B: Both sentences will be gray.
C: Sentence 1 will be pink, Sentence 2 will be gray.
D: Both sentences will be pink.
E: The code does not make sense; will throw an error.

In the following HTML, what will be the color of link with class "mark"

Consider the following HTML and CSS:

Which additional CSS rule(s) will render the following image? Choose ALL that apply.

A:
div{
  flex-direction : column;
  align-items : center;
}

B:
div{
  flex-direction : row;
  align-items: center;
}

C:
div{
  flex-direction: column;
  justify-content: center;
}

D:
div{
  flex-direction: row;
  justify-content: center;
}

We want to register students for the next semester. All students have a receipt which shows the amount pending for the previous semester. A positive amount (or zero) represents that the student has paid extra fees, and a negative amount represents that they have pending fees to be paid. The students are in a queue for the registration. We want to arrange the students in a way such that the students who have a positive amount on the receipt get registered first as compared to the students who have a negative amount. We are given a queue in the form of an array containing the pending amount.

For example, if the initial queue is [20, 70, -40, 30, -10], then the final queue will be [20, 70, 30, -40, -10]. Note that the sequence of students should not be changed while arranging them unless required to meet the condition.

⚠️⚠️⚠️ Note:
- The first line of the input is the length of the array. The second line contains all the elements of the array.
- The input is already parsed into an array of "strings" and passed to a function. You will need to convert string to integer/number type inside the function.
- You need to "print" the final result (not return it) to pass the test cases.

For the example discussed above, the input will be:
5
20 70 -40 30 -10

Your code needs to print the following to the standard output:
20 70 30 -40 -10

A startup company E-Motors is building driverless automated cars. The car contains a sensor that checks the road quality for the next N meters to decide the optimal speed at which the cars should move. We are given recorded data by the sensor in the form of an array, where each element of the array is the rating given to 1 meter of the road in sequence. 

The rating given by the sensor is from 1 to 100, where 100 represents the road with the best condition, and any rating above 60 is optimal. Find the longest stretch of road in meters that is categorized as optimal by the sensor.

The input is an array of "strings" which needs to be converted from string to integer/number inside the function.

A manager hires a staff member to keep a record of the number of men, women, and children visiting the museum daily. The staff will note W if any women visit, M for men, and C for children. You need to write code that takes the string that represents the visits and prints the count of men, woman and children. The sequencing should be in decreasing order. 

Example:

Input:
WWMMWWCCC

Expected Output: 
4W3C2M

Explanation: 
‘W’ has the highest count, then ‘C’, then ‘M’. 

⚠️⚠️⚠️ Note:
- The input is already parsed and passed to a function.
- You need to "print" the final result (not return it) to pass the test cases.
- If the input is- “MMW”, then the expected output is "2M1W" since there is no ‘C’.
- If any of them have the same count, the output should follow this order - M, W, C.