I recently went for an interview with Schlumberger – one of the giants in the oilfield sectors. I qualified their coding test comprising of two coding questions and six multiple-choice questions.
After that, I got a call for an interview, which consists of four rounds – two technical, one TCM and one HR.
In the first technical round interviewer straight away jumped to coding questions after a little introduction. Questions asked were –
- Given a list of array elements with all unique elements, except one element which comes two times, find that duplicate number. It was similar to this Repeating element except the array elements were not from 1 to n. I gave him the hashing solution but he wanted it in O(1) space complexity and O(n) time complexity.
- The second question he asked was this – In an array, all elements are repeated twice except one element which comes thrice, find that element. I gave him the simple XOR solution, where we XOR all the elements and the final result is the answer.
- He then moved on with trees and asked me about the binary tree, BST, Complete binary tree, etc. He then asked me to insert elements in a Binary search tree. He wanted the code for that, So I wrote the entire code for adding functionality.
- He asked about the traversals of the binary tree, I told him – inorder, preorder, postorder, level order, etc. He then asked me to write the code for level order traversal.
- Finally he improvised the problem and asked me to write the code for zig-zag traversal. Link is – zig zag traversalThat was all for the first round, then I moved for the second round where he just wanted to understand my ability to understand OOPS concepts. He gave me some scenarios for which I had to make classes and methods on whiteboard according to my understanding of the problem. The interviewer was friendly and told me that there is no right or wrong answer so I could approach the question however I want.
After this, there was a TCM round, where they basically want to know about your tech awareness and which language or technology you like and want to work with.
The last round was HR where they ask about your strengths and weaknesses, how are you as a person, what are your salary expectations, why do you want to work with us and all.
Overall if you have at least done Must Do Coding Questions in gfg, the technical interviews won’t be a problem.
Good Luck !!