Meta Software Engineer Full Stack Web interview questions

I have applied directly on website as l see the position is listed on stackoverflow.com. The recruiter contacted me to ask for time for a call and she confirmed one of the date l suggested. She called on the exact time as scheduled, she gives some introduction and ask me to tell my background. And then she asked me some data structure questions. Unfortunately I wasn't prepared for technical questions and l couldn't answer. She told me we couldn't continue because I failed to answer the questions, but I can improve myself and apply again in after 6 months or later. And then she explained the interview process and and about the boot camp after selecting. The experience was pretty good she was very punctual, friendly and supportive.