# GreyOrange Interview Experience | Set 1 (Backend Developer Profile)

• Last Updated : 01 May, 2018

There were 5 rounds. 2 coding and 3 interviews. Both coding rounds on hackerrank platform:

First Coding round :
1) A matrix containing 0’s and 1’s. Set whole row and column of a cell containing 0 to all 0’s.
Reference : http://stackoverflow.com/questions/339262/set-every-cell-in-matrix-to-0-if-that-row-or-column-contains-a-0

2) convert a number m to n with minimum operations. The operations allowed were -1 and *2.
For Eg : 4 and 6. Answer is 2.
1st operation : -1 -> 4-1 = 3.
2nd operation : * -> 3 * 2 =6.

Second Coding round:

1) Given a matrix containing O’s and X’s. Convert all O’s to X’s which are fully surrounded by all X’s.
Approach : First handle the boundary O’s and say change them to some other character say *. Now for all the remaining inside O’s check applying DFS if there is a way out ie, if the DFS reaches the character *. If not then convert all O’s to X’s in that matrix.

2) Direct knapsack problem.

3) Implement circular linked list with dynamic insertion and deletion with minimum time complexity. Queries were given during runtime, for insertion and deletion. After n such operations, print the linked list again.

First Round :

1) detect cycle in a linked list and the point where the cycle begins.
2) Min stack implementation.
3) Modified previous question and asked to find the middle element in this stack in minimum time complexity.
4) Questions asked in the coding test, asked some changes to optimize the algorithm.
6) Design patterns overview, and describe any two of them in detail.

Second Round :

7) Virtual functions, Interfaces, polymorphism both static and dynamic.
8) Design a system similar to geryorange where there is a central server monitoring all the robots(It was bit simple and direct).
9) Any versioning system. I said Git.. they looked over my git profile.
10) Favourite subjects : I told them cloud computing, then they asked me many things related to Docker containers.
11) Projects obvious, they asked me 3 projects.

Third Round :
This was on phone, where he asked me all the technologies I have worked on. Then again there was a discussion on GIT and NoSQL databases. Why not SQL ?.
And again they asked me a project and it was finally done (y).

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