First round was normal - simple question and code logic - Delete a Node in Linked List , Find missing number is sorted array Second round was collaborative - Interviewer was involving .questioning on your understanding in every detail - which language do you like most and why ? Show me examples on your understanding of a particular topic(destructor/scope). Implement stack API(How is min size of stack is considered). Questions on why are we asserting at checking the valid i/p in API , why do you have certain return values and example of how your stack is used. Implementation of malloc , why is header used in malloc .How more efficient can you decrease the size of header. Final Round-Hiring Manager round- started with a DS implementation, how does switchsave the IP address of a route in Data structure. what is/Implement Patricia tree. How are bytes order in a switch (when we are programming code - will it be in little endian/big endian and will it be hton/ntoh). Best way to save space of a DS.( Never use int , use only uint32_t .) The way you give naming to a variable is very important and the way you write comment to your API's. - Naming of variable is imp - Use as less amount data as possible to achieve a functionality. (uint32_t vs int ) - Know how address format will be on switch (programming)(ntoh or hton / big endian /small endian) - Its ok if you dont know a DS , be strong with basics.