HashedIn by Deloitte Technical Analyst interview questions

First round was written test which included 7 objective type questions and 3 programming questions. The 7 objective questions were about time complexity, DBMS queries, postfix infix expressions, io question and the programs included a virtual keyboard traversal, bst deleting half node, parenthesis balancing. Out of 250- 300 odd 12 were selected. 2nd round was technical round where they gave a program and asked to reduce the complexity. Out of 12 , 11 were selected. Third round was face to face technical interview in which they asked me to explain the logic of the virtual keyboard program, one array program, the complexity of the same program was asked to be reduced which I couldn't do. Next was reducing the complexity of BST deleting single node program. This was the round I was rejected. Be thorough with complexity and learn how to reduce the complexity of a program. All the best.. Concentrate on COMPLEXITY and Trees. :)