23 OVH Cloud Interview Questions and Answers | Assessment Test

I attended the OVH cloud interview in Bangalore, India. Here I’m sharing OVH cloud interview questions and my experience.  I have 5 years of experience. But they had multiple opening at multiple levels. There were some freshers as well.

For me, their hiring process includes one pen-paper round (assessment test) and a technical interview with the project lead.

Round 1: OVH Cloud  Assessment Test

This is the pen-paper written test.

An assessment test was common for all the freshers and experienced candidates.

There were 10 questions from coding, data structure, and database. You have a time of 30 minutes to answers these questions.

Question 1: What is the REST API?

Question 2: You have given an array of integers. Find the elements in the array which occur only once and all other elements occurs twice.

Answer: Use an XOR operation. Here is a simple Python program.

```def findUnique(arr):
out=0
for i in arr:
out=i^out
return out

print(findUnique([2, 4, 3, 3, 2, 5, 5]))
```

Output:

`4`

Similar questions were asked to me in the NVIDIA job interview.

Question 3: You have given a tree. Find the post order traversal of it.

Output:

`Postorder traversal of the above tree: 7 3 1 6 5 4`

Question 4: What is the time complexity of the in-order traversal of the above tree?

Answer: Every node in the binary tree is visited thrice.

```Time complexity:
~= 3 * O(n) - where n is the number of nodes in the binary tree.
~= O(n)```

So it takes a linear time for traversing any all the nodes in the binary tree.

Question 5: Write an algorithm to check whether two strings are a rotation of each other. Example: ‘abc’ and ‘bca’.

Answer: Here is the simple algorithm you can use to verify if the two strings are a rotation of each other or not.

```Suppose two strings are str1 and str2.
If the length of the two strings are not the same:
- return false.
else:
-  Concatenate str1 to the same string says temp (str1+str2)
- if the str2 is a substring of temp, returns true. Else, return false.```

Question 6: Find if the given number is odd or even without doing any arithmetic operation.

Answer: Convert the given number into the binary number. If the last bit of the binary number is one, the number is odd. If the last bit of the binary number is zero, the number is even.

Python Code:

```def reminder(a, b):
if a==0:
return 0
elif b==0:
return -1
while a >= b:
a=a-b
return a

print(reminder(34, 6))
```

Output:

`4`

Refer to finding a reminder without using a modulus operator. You can find algorithms, problems solved in Python, C/C++ and Java with detailed explanations.

If you get the logic, it is easy to implement in any programming language.

Question 7: What is a foreign key in a database?

Answer: Foreign key in the database is the derived primary key of another database table. Check the different types of database keys, where we have explained each database key with examples.

Question 8: Write a regular expression that accepts any number of a* which should not be followed by more than 3 b’s.

(Sometimes, the interviewer can also ask you to write a program for it. If you are a Python developer, knowing Python RegEx syntax will be very important.)

Question 9: Write an algorithm to check if the given string is a palindrome or not.

Question 10: Print all the valid parentheses (open and close brackets) for the given n-number of parenthesis pairs.

Answer: You can solve this with the recursion.

Hint:

• For valid parenthesis, if you traverse from left-to-right, the number of the closing bracket should not exceed the number of opening brackets anytime.
• You can use the stack to validate if the string with parenthesis is valid or not. If it is an opening bracket, push it in the stack. If it is closing bracket pop up the opening bracket. Do this for all the elements in the string. In the end, if the stack is empty, the string has a valid parenthesis sequence.

To crack this round, practice solving coding interview questions.

Round 2: OVH Cloud Interview Questions

After the written test, the hiring panel asked me to go for a technical interview.

We started with a brief introduction. The interviewer told me about the work they are doing and about the company.

This was was the complete technical interview round. There was a whiteboard in the meeting room. You have to explain it on the whiteboard.

Question 11: My current project is related to the REST APIs. He asked me to explain the high-level design of the project on the board. He asked some questions related to the REST APIs and my project.

Question 12: How to implement post order traversal without recursion?

Hint: We can implement a post-order traversal algorithm using the stack.

Question 13: You have given two numbers (says ‘a’ and ‘b’). Write a program to find the reminder by diving ‘a’ by ‘b’ without using division or modulo operation.

Question 14: What is the data structures in Python to store the array elements?

Question 15: What is the difference between the list and tuple?

After a few days, I got a call from the HR team and they asked me to come to their office for further interview rounds.

Round 3: Data Structure And Algorithm OVH Interview Questions

This round was purely on data structure and algorithm. There was a big whiteboard and the interviewer asked me to write code for the following coding questions. (Difficulty level was moderate.)

Question 16: Print all the valid (balanced) parenthesis.

Question 17: Print post-order traversal of the binary tree without using recursion. (Post-order traversal with recursion is pretty easy. You have to solve this using iteration.)

Question 18: You have given three strings (says str1, str2, str3). Write a program to check whether str3 is the interleaving of str1 and str2.

You can choose any programming languages. I chose Python.

Then he asked me one simple but tricky question.

Question 19: How to reverse the string in Python with a single line of code without using any inbuilding function?

```msg="code"
print(msg[::-1])
```

Output:

`edoc`

After this, I was asked to give one more interview to the manager.

If you are preparing for a Python developer job, check Python interview questions and answers.

Round 4: Interview with Manager

Question 20: Asked me to draw the hight level design of my current project. He asked me for some deigning questions about it.

Questions 21: As I have mentioned redfish in my project. He asked- What’s redfish? (Whatever you mention in your CV, prepare well.)

Question 22: What are the different HTTP method types?

Answer: Here are the basic HTTP methods and their uses.

• The GET method is used to retrieve the information.
• POST, PATCH, and PUT are used to write or update resources.
• OPTION is used to get header information.
• DELETE is used to delete any resource on the server.

Question 23: OVH cloud provides cloud services to the client. How to store and retrieve server configuration data?

Answer: There are multiple ways of managing configuration data. Configuration data are usually in the key-value format. This type of data can be saved in formating languages like JSON, XML or YAML.

Depending on the project demands, these types of data can be saved in the databases. There are many advantages of storing data in databases rather than in plain text files.

If you want to do it more programmatic way, we can define the structure/class to store the data. Create an object and save the data. We can save this object in plain text files which can be retrieved later. In Python, we call it pickling and unpickling.

There were a few more questions that I’m not remembering right now. The interviewers were very friendly.

This interview almost went for an hour. This is all about my experience. All the best!

Editor’s Note: These OVH cloud interview questions and assessment coding experience are shared by the candidate. We wish him all the best.