Perfios SDE interview experience

1st Round: Pen and paper round. 4 DSA linked list question. Aptitude questions were also there in this round. This round was 75 to 90 minutes. 2nd Round: F2F interview. Asked me about the DB Schema and API structure of my internship work. Fundamental questions on DBMS. 1 leetcode question similar to repeated DNA sequences. Was not able to write the code for the DSA question. 3rd Round: Basic stack question. Fundamental OS questions. Asked the approaches of the questions in the 1st round. 4th Round: Managerial round. Find the repeating character in a string in O(1) time and O(1) space complexity. Extensive discussion on my internship experiences. Some typical managerial questions. Check if a given tree is a subtree of a another tree. 5th Round: Asked me how alarms work in phones. Real life applications of DSA.