Gartner Team Leader interview questions

They took 6 rounds and had to wait for about 2 months to know the final outcome. After clearing 6 rounds, the HR stopped picking calls, I haven't seen such improfessional HR in my entire life. After 1 month of follow up, I got email stating that I have not got selected, I was shocked to see the outcome as I was pretty much sure about my selection. It looked to me that they were wasting my time and they had already given an offer to candidate and were just waiting for him/her to join and at the same time preparing a backup. I will say that no one should ever apply in gartner until they want to waste their time and get frustrated by undeducated HR.