Google Off-Campus [SDE-1]

I interviewed for Google recently and here is my experience in detail. The interview process took around 5 months for completion as they provide you ample amount of time to prepare for your interviews so when you appear for the interview you are in your best form.

HR Round: Google was first company where HR herself took a small rapid-fire round to test if the candidate is even worthy for scheduling a telephonic screening with one of the Google engineer.
Few questions:

1. Worst time complexity for Heap sort?
2. Merge sort is better or Heap sort? And why?
3. Does Quicksort complexity depends on what pivot element we choose like middle one, rightmost one or leftmost one?
4. What is the value of 2^24? (Here HR wanted to check how would I approach this calculation provided I don’t have any calculator with me.)

The round was easy for someone who is preparing for Google but it might come as a surprise for some who are not expecting this and might end up giving wrong answers.

Telephonic Round: This round went for exactly 45 mins. The interviewer went straight for the question. In this round it is crucial that you manage the time, code readability & obviously the correctness of the solution that you provide. Moreover you have to code on Google Docs so indenting the code is important for maintaining clean code.

Question: You are given 2 strings which are exactly same but 1 string has an extra character. Find that character.

Approach: Sort the strings and keep matching until you find that extra character because it won’t be present in other string. Time Complexity – O(nlogn).

He asked me to code the solution. After this he asked me to further optimise it without sorting the strings.