Ciena | India | Intern | On Campus | Rejected

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

This round had three sections:

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:

I started with a self-introduction. The first technical question was to write the syntax of a void function pointer that takes two integers as input and then assign this function pointer to a real function.
Other questions included:

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.

I really struggled with many pointer syntax questions, especially regarding the placement of & and *, and felt nervous. At one point, the interviewer asked what topic I was confident in, and I mentioned data structures and algorithms. He then asked for the difference between struct and union, which I couldn't answer, and he commented, 'but these are data structures ;('.

Round 2: (20 out of 35 students shortlisted)

This round also started with a basic introduction.

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.

I answered most of the questions and puzzles in this round, although I got stuck several times and confidently gave wrong answers to some pointer-based questions. I felt the second interview went much better than the first.

Result: 10 out of 20 students were selected, but I was rejected. Overall, the experience was good, and the interviewers were polite and friendly.