Freecharge Interview Experience-Lead SDE

Round1 1) Design, develop and implement an elevator problem (only 20 minutes) Lots of discussion on why the approach is chosen. Advantages and trade-offs discussed.(For a...

Round1 1) Design, develop and implement an elevator problem (only 20 minutes) Lots of discussion on why the approach is chosen. Advantages and trade-offs discussed.(For almost an hour)

Round2 1) All possible permutations of a string. 2) Design, develop and implement Phone directory. Implement a search algorithm on top of it ..so that it does autocomplete Eg : %95% (

Result 98769512345, 9545654312 etc having 95 sequence anywhere) (Note : Not to use TRIE) 3) Design, develop and implement an OrderGenerating System in distributed servers. Conditions: 1) No database should be used. 2) The orderID generated should be unique among all servers. Lots of discussion on various approaches. 4) Difference between equals and hashcode in JAVA Round3:(Hiring Manager Round) 1) Details about projects in CV.Explanation in detail 2) Check if Binary Tree is BST or not?