Antra Software Development Engineer (SDE) interview questions

I had two interview with them. First interview was a basic interview through phone and second interview was a about basic technical concepts. And they told me that, Once you pass the first two rounds of interviews, they will send me an invitation letter to to attend our 7 weeks of online training. After the 7 weeks of online training, I also need to do unpaid marketing for 3-4 weeks.

Two questions related to front end web development about generate random string as an invitation link and another one is designing query parameter for a drop down list. One leetcode medium question is asked afterwards.