Please don't give their problem-solving round. I can't believe they cannot understand algorithms. This was like the funniest interview, where I enjoyed the interviewer's knowledge of DS. For one of the questions, I used an outer while loop for an exit check and there was an inner while loop, basically getting incremented on some condition that I put. Finally, I had to make sure that I don't come out of the loop without completing the iteration of the entire array, so that was just an exit condition to check. I explained why it's O(n). Funny, hilarious! Since he saw two loops, he was like, 'Two while loops, it is O(n^2).' Anyway, I gave up. I was like, 'Why not!' Also, it's one of the easy questions on LeetCode, Buy and Sell Stock.

1. Buy and sell stock

2. Copy linked list with random pointer