Meta Software Engineer interview questions

5 rounds coding phone interviews, plus onsite. Failed the last phone interview interview. They check for a mix of coding, OOD, system design. Have a look at Cracking the Coding Interview,

I went through the initial phone screen at meta and it was relatively expected. I was asked two leetcode medium style questions, one I had seen before but slightly altered. I didnt do well on the first question but the second one I got perfect with an optimal solution. I didnt end up moving forward however, which tells me you need to get both questions at least close to optimal.