TikTok | OA | 11/03/2024

Round 1

Questions:

1. Implementing a Real-Time Operating System (RTOS)
   TikTok is developing an embedded system that requires a real-time operating system (RTOS) to ensure timely task execution.
   Which RTOS feature is most critical for ensuring real-time performance?
   Pick ONE option

   • Preemptive multitasking
   • Virtual memory
   • File system support
   • Multi-user support

2. Call Center Queue Optimization (Circular Queue)
   You are implementing a call center software where customer calls are processed in the order they are received. The call center uses a circular queue to optimize memory usage.
   Implement the function enqueue (call) in a circular queue.
   Which of the following pseudocode correctly implements the enqueue operation for a circular queue?

   Function initializeQueue (size) :
       maxSize = size   # Initialize Max Size
       front = 0   # Initialize front pointer
       rear = 0  # Initialize rear pointer

3. File Compression (Huffman Encoding)
   Your company is developing a file compression tool using Huffman encoding. You need to implement the function that builds the Huffman tree based on character frequencies.
   Which of the following pseudocode correctly builds the Huffman tree?

   Function buildHuffmanTree (frequencies) :
       Create a priority queue Q
       For each char in frequencies:
           Insert char into Q with frequency as priority
       While Q.size > 1:
           left = Q.extractMin()
           right = Q.extractMin()
           newNode = Merge left and right
           Insert newNode into Q
       Return Q.extractMin()

4. Object Lifecycle and Resource Management in a Banking System
   In a banking application, you are tasked with implementing a BankAccount class that manages customer accounts, including account opening and closing. The BankAccount class must handle external resources like file logging for transactions. Which of the following OOP design ensures that resources are properly cleaned up after use, even when exceptions occur?
   Pick ONE option

   • Use of constructors to open resources and System.exit() in finally blocks to close them
   • Use of a destructor del() in Python or finalize() in Java to close resources when the object is garbage collected
   • Implementing the AutoCloseable (Java) or enter/exit (Python) pattern for resource management
   • Relying on the JVM or Python interpreter's garbage collector to automatically close all resources

5. Encapsulation and Access Control in an E-Commerce Platform
   You are developing a class Order for an e-commerce platform. This class handles customer orders, including sensitive information like payment details. Which of the following best demonstrates proper encapsulation to protect sensitive data?
   Pick ONE option

   • Make all attributes of the Order class public so that external classes can modify them directly
   • Use protected attributes and provide public getter and setter methods for all attributes
   • Declare sensitive attributes like paymentDetails as private and provide only necessary getter methods, without setters
   • Define all methods as private to ensure no other class can access the functionality

Counting TikTok Creator Communities

In TikTok's ecosystem, creators often form communities and collaborate within them. These relationships can be represented by a matrix related, where each cell related[i][] contains a binary value ('0' or '1'). A '1' in related[i] means that Creator i and Creator j are directly connected, while a '0' means they are not connected.
Creators can also be connected through indirect connections. For example, if Creator A is connected to Creator B and Creator B is connected to Creator C, then Creator A is indirectly connected to Creator C.
All creators that are connected, either directly or indirectly, form a distinct community. No two creators from different communities are connected to each other, either directly or indirectly.
Your task is to return the number of distinct creator communities based on the given relationship matrix related.

Function Description
Complete the function countCreatorCommunities in the editor below.
countCreatorCommunities has the following parameters:
string related[n]: An array of strings of binary digits related[i] that represent the connection between creators.

Returns:
int: An integer that represents the number of distinct creator communities.

Constraints
• 15 ≤ n ≤ 300
• 0 ≤ related[i] ≤ n
• Each related[i] contains a binary string of n zeros and ones. related is a square matrix.

TikTok User

A TikTok developer is creating a method to give numbers to users, shown as an array arr.
The arrangement of numbers is called "good" if the difference between any two numbers next to each other is 1 or less. For example, the array [1, 2, 1] is good, but [2, 1, 3] is not, because the difference between 1 and 3 is 2, which is greater than 1.
The array arr has n numbers, but some numbers are missing. These missing numbers are shown as arr[i] = 0. The goal is to find how many ways you can replace the missing numbers with any arbitrary integer numbers, so the final array is "good."
Since the number of ways can be very large, return the answer as the remainder when divided by (10^9 + 7).
Note: The array arr initially contains elements in the range -10^9 ≤ arr[i] ≤ 10^9. However, the indices with missing values (arr[i] = 0) can be replaced with any arbitrary integer to make the final array "good."

Function Description
Complete the function countGoodArrays in the editor below.
countGoodArrays has the following parameter:
int arr[n]: an array of integers

Returns
int: The number of ways to replace missing elements to form a good array, modulo (10^9 + 7).

Constraints
• 1 ≤ n ≤ 1500
• -10^9 ≤ arr[i] ≤ 10^9
• There is at least one element in arr which is not equal to 0.