Google Internship Interview Experience

I got call for interview by Kickstart, I participated in Kickstart 2019 round A and B and has secured rank 186 and 181 respectively. They told me that there would be 2 rounds, First is telephonic and another is on hangout. They shared 2 google doc links with me to write code during interview. 

Round 1(Telephonic Round: 45 minute): I got an system generated call which then connected me to the interviewer (Not Indian), He first introduced himself and then asked me to introduce myself, Then he moved to problems. 

1. Given an N-ary tree . You have to traverse the tree in preorder and at each node you need to print value of node and number of childs it has. I solved this then he started to make it harder and told me that whatever my code is giving me as output is now my input and I have to construct the tree again. I was like wooow(Pin drop silence for 5-10 minutes), I was unable to think anything now, I just told him that how can we solve this problem but I was unable to implement it. And then he moved to next problem.
2. Given array of N number and you need to return the element which repeats, If there are multiple elements which repeat, return the first one. I’ve solved this then He changed it slightly and told me that now I’ve to return number which repeats maximum number of times, I solved it too. After this he has changed it and now I have to return maximum number which repeats. I solved all of these.

Then at last he told me that I can ask anything to him, I asked some questions and he answered. 

Round 2 (Hangout Round : 45 Minute): I was having link to video call which I joined on time, Then I asked Interviewer(Not Indian) If  he can see and hear me properly or not, Then we both introduced each other and he moved to the problems. 

1. Given two arrays and I have to find common elements between both arrays. First I’ve solved it using Binary Search with O(nlogn) time complexity. Then he told me that I should output one element only once if it is present more than once in both arrays, I did fixed this. Then he told me to optimize time complexity, Then I used Unordered Map and solved it in O(n) and then he told me that now I have both arrays already sorted and I have to find solution in O(n) time complexity and O(1) space complexity. I solved this using Two Pointers, Then he gave me 2 3 test cases and told me to run my code on these test cases virtually and I did.
2. This problem was a little bit harder version of the previous problem. This time I was given a matrix which was sorted row-wise and now I have to return numbers which are common in all rows. I solved it using N pointers in O(N*M) complexity and then he told me to run on test cases and I did.

Then at last he told me to ask anything, I again asked some questions and he answered.