PTC Java Developer Interview Questions and Answers

Round duration - 90 Minutes
Round difficulty - Medium

It was an online technical round. There were around 20 MCQs and two coding questions. The round had an login window of 30 minutes. One coding question was of the level leetcode medium and the other was leetcode hard.

Q1. 
Search in a Row-wise and Column-wise Sorted Matrix Problem Statement
You are given an N * N matrix of integers where each row and each column is sorted in increasing order. Your task is to find the positi...read more
Add your answer
Q2. 
Euler’s Totient Function Problem Statement
Given an integer N, your task is to determine the count of integers between 1 and N (inclusive) that are coprime to N.
Input:
The first line contains an intege...read more
Ans. 
Euler's Totient Function calculates count of integers coprime to N between 1 and N.
• Implement Euler's Totient Function to calculate count of coprime integers to N.

• Use the formula: phi(N) = N * (1 - 1/p1) * (1 - 1/p2) * ... * (1 - 1/pk) where p1, p2, ..., pk are prime factors of N.

• Example: For N = 9, phi(9) = 9 * (1 - 1/3) = 6.
Answered by AI
Add your answer

Round duration - 60 Minutes
Round difficulty - Medium

It was a technical + HR round. The interview panel consisted of two technical guys and one person from HR.

Q1. 
Sort Array of Strings Problem Statement
Given an array of strings ARRSTR[] of size N, and a character C, your task is to sort the ARRSTR[] array according to a new alphabetical order that starts with the ...read more
Ans. 
Sort an array of strings based on a new alphabetical order starting with a given character.
• Iterate through the array of strings and compare each string with the given character to determine the new order.

• Implement a custom comparator function to sort the strings based on the new alphabetical order.

• Use built-in sorting functions in programming languages like Python, Java, or C++ to efficiently sort the array.
Answered by AI
Add your answer
Q2. Can you explain the pillars of Object-Oriented Programming (OOP)?
Ans. 
The pillars of OOP are Inheritance, Encapsulation, Abstraction, and Polymorphism.
• Inheritance allows a class to inherit properties and behavior from another class.

• Encapsulation restricts access to certain components of an object, protecting its integrity.

• Abstraction hides complex implementation details and only shows the necessary features.

• Polymorphism allows objects to be treated as instances of their parent class, ena...read more
Answered by AI
Add your answer

Round duration - 75 minutes
Round difficulty - Hard

Coding Test with 3 problems. 1 Easy , 1 Medium , 1 Very Hard

Q1. 
Job Scheduling Problem
You are provided with a list of jobs, where each job has a specific deadline and profit. The goal is to schedule these jobs such that the total profit is maximized. Each job require...read more
Ans. 
The goal is to schedule jobs to maximize profit while meeting deadlines. Each job takes one unit of time and only one job can be scheduled at a time.
• Sort the jobs in decreasing order of profit

• Iterate through the sorted jobs and schedule them based on their deadlines

• Keep track of the total profit achieved

• Ensure each job is completed before its deadline
Answered by AI
Add your answer
Q2. 
Spiral Order Traversal of a Binary Tree
Given a binary tree with N nodes, your task is to output the Spiral Order traversal of the binary tree.
Input:
The input consists of a single line containing elem...read more
Ans. 
Implement a function to return the spiral order traversal of a binary tree.
• Traverse the binary tree level by level, alternating between left to right and right to left.

• Use a queue to keep track of nodes at each level.

• Append nodes to the result list in the order they are visited.
Answered by AI
Add your answer
Q3. 
Structurally Unique Binary Trees of Dragon Balls
Goku has ‘N’ Dragon Balls, where each Dragon Ball is unique. The ith Dragon Ball has ‘i’ stars on it, meaning the first Dragon Ball has 1 star, the second ...read more
Ans. 
Count the number of structurally unique binary trees that can be constructed with given Dragon Balls.
• Use dynamic programming to solve this problem efficiently.

• The number of structurally unique binary trees can be calculated using Catalan numbers.

• For each test case, calculate the number of structurally unique binary trees modulo 10^9 + 7.

• Return the count of unique binary trees for each test case.
Answered by AI
Add your answer

Round duration - 60 minutes
Round difficulty - Hard

In depth questions on Subjects like OOP , DBMS , OS , Javascript.

Round duration - 40 minutes
Round difficulty - Hard

Questions on my resume, projects, internship done. Interviewer was a bit harsh on me.

Q1. What are the differences between low-level and high-level programming languages, and can you explain some kernel-related questions?
Ans. 
Low-level languages interact directly with hardware, while high-level languages are more abstract and easier to read/write.
• Low-level languages are closer to machine code and hardware, while high-level languages are closer to human language.

• Low-level languages require more manual memory management and are less portable, while high-level languages have automatic memory management and are more portable.

• Examples of low-lev...read more
Answered by AI
Add your answer

Round duration - 45 minutes
Round difficulty - Medium

Technical Interview round with questions on DSA.

Q1. 
Reverse Words in a String: Problem Statement
You are given a string of length N. Your task is to reverse the string word by word. The input may contain multiple spaces between words and may have leading o...read more
Add your answer
Q2. 
Reverse a Stack Using Recursion
You are given a stack of integers. Your task is to reverse the stack using recursion without using any extra space other than the internal stack space used due to recursion...read more
Ans. 
Reverse a stack using recursion without using any extra space other than the internal stack space.
• Use recursion to pop all elements from the original stack and store them in function call stack.

• Once the stack is empty, push the elements back in reverse order.

• Base case of recursion should be when the original stack is empty.
Answered by AI
Add your answer

Round duration - 45 minutes
Round difficulty - Medium

Technical Interview round with questions on DSA.

Q1. 
Convert a Binary Tree to its Mirror Tree
Given a binary tree, convert this binary tree into its mirror tree. A binary tree is a tree in which each parent node has at most two children. The mirror of a bin...read more
Ans. 
Convert a binary tree to its mirror tree by interchanging left and right children of all non-leaf nodes.
• Traverse the binary tree in a recursive manner.

• Swap the left and right children of each non-leaf node.

• Continue this process until all nodes have been processed.
Answered by AI
Add your answer
Q2. 
Remove Nth Node from End of Linked List
You are given a singly linked list with 'N' nodes, each containing integer data, and an integer 'K'. Your goal is to remove the 'K'th node counting from the end of ...read more
Ans. 
Remove the Kth node from the end of a singly linked list.
• Use two pointers approach to find the Kth node from the end.

• Handle edge cases like removing the head node or removing the last node.

• Update the pointers to remove the Kth node and reconnect the list.
Answered by AI
Add your answer

Round duration - 30 minutes
Round difficulty - Easy

Typical Managerial round.