Pocket Gems Software Development Engineer Summer interview questions

Received a java OA several days after online application. Asked HR if I can take a C++ OA instead. They scheduled a initial phone interview for me. The questions are not difficult. Coding challenge: the first one is to implement strStr and give the worst case. Can't remember other questions. Each question comes with several follow ups. Generally speaking, the coding challenge is quite easy, some follow ups may be a little tricky.