I implemented good, but still got rejected after discussing with the 1st interviewer, that also I went at 10 am and got result of 1st round at 5 pm, now you can imagine their process. Couple of things why these companies conduct drive - 1. Not necessarily they are in urgent need 2. HR department wants to show they are working 3. Interviewers ask their senior managers about some random design questions 4. BOOM ! solve it , it's so open ended that sometimes even you won't know why did you get rejected. 5. Now a days these hiring events are just for showing off , nothing else .