I interviewed for an Intern position at Ciena during their campus placements in November '24. The internship was for 6 months, from January to June 2025, with a stipend of 35k for B.Tech students and 40k for Masters students.

First Round: Online Assessment

1. Coding Round: 25 Minutes
   • Q1. I was asked to check if a number's binary representation is a palindrome. This question was exclusively in C, with no other language options.
   • Q2. The second question involved an arrangement of students with given heights. I needed to print the indexes of students who were not standing in increasing height order. This question allowed C++.
2. Programming Languages Round: 30 Minutes This was an MCQ round focused on syntax. Many confusing pointer-based questions were asked, covering references, pointer arithmetic, and function pointers—basically, deep questions about C language pointer syntax.
3. Aptitude Round: This section consisted of 5 basic aptitude questions that high school students could solve.

Face to Face Interviews

Round 1:

1. A malloc syntax-related question, asking what malloc returns.
2. What are static variables, and the difference between static and global variables.
3. If a struct stores 2 integers and 1 char, how much memory does it occupy? Follow-up: Where is that padding stored internally?
4. How to find the middle of a Linked List? Follow-up: If there's an even number of nodes, what would the code return, and how can we configure it?
5. How to avoid deadlock, specifically mentioning the 4 conditions.
6. The difference between struct and union.
7. To reverse the words in a sentence, and I had to write the code on paper.
8. I was asked to explain one of my projects in detail.
9. The difference between semaphores and mutexes.
10. The difference between declaration, initialization, and definition for a variable.

Round 2: (20 out of 35 students shortlisted)

1. What would happen if malloc(0) is used?
2. Write the syntax to declare an array of size 10 that stores pointers to integers, and then declare a pointer to an array of size 10 that stores integers.
3. Given a syntax snippet:

   int x = 10;
   int *ptr = x;
   ++(*ptr);
   

   I was asked what *ptr would return.
4. To find a duplicate element in an array containing numbers 1 to n, where exactly one element has a duplicate. I initially started writing C++ code but was asked to switch to C. I then wrote the standard slow pointer and fast pointer code for this problem. I had to explain in detail how the code works, including when the cycle is detected and then when the duplicate element would be detected. I was also asked if the code would run in O(n) time. I initially said yes, but the interviewer questioned if I was sure, suggesting that pointers might be pointing to indexes randomly, which led me to change my answer, admitting the loop might run more than n times.
5. Puzzle: If there are 4 jars with infinite 10g balls and 1 jar with infinite 9g balls, how would I detect the defective jar if I could only weigh once?
6. Why do we use mutexes?
7. Discuss static variables. Have I ever heard of the volatile keyword, why do we use it, and how exactly does the compiler 'optimize' a variable if we don't use volatile?
8. There was a discussion on whether I had studied compiler design or written assembly code. I talked about my knowledge of the 8086 processor.

My interview experience at Ciena for the UI Developer position involved a comprehensive 90-minute technical round. The discussion covered a wide array of front-end development concepts, starting with advanced JavaScript topics such as higher-order functions, pure functions, and the intricacies of call, apply, and bind methods. We then moved into React, exploring higher-order components, pure components (both functional and class-based), shallow vs. deep comparison, various hooks (useEffect, useRef, and their specific use cases), and how to prevent unnecessary component re-renders.

Redux was also a significant part of the interview, where I was asked about its three principles, how to write a reducer, the use and advantages of middleware, and the in-depth flow of how Redux identifies which reducer should be called. Additionally, I was presented with two coding challenges: one to create a polyfill for the call method and another to write a program using the reduce method to count continuous characters in a string, for example, transforming 'aaabbccaa' into '[{a:3}, {b:2}, {c:2}, {a:2}]'. Unfortunately, after this round, I never received any further communication from the recruiter.