Q1: Which ones are O(log N) cost operations, on average, for a set data structure that is implemented as a binary search tree? (a) size(), insert(T&) and erase(T&) (b) empty(), size(), and insert(T&) (c) find(T&), insert(T&) and erase(T&) (d) empty() and size() only.

Q2: The following function is to remove all values equal to 0 from a vector of integers. void remove_0s(Vector& vec) { int * itr = vec.begin(); while (___________) // << (1) { if (*itr == 0) vec.erase(itr); ______________ // << (2) } return; } Blanks (1) and (2) are to be filled with the correct C++ statements. These are (a) itr <= vec.end() for (1) and else itr++; for (2). (b) itr < vec.end() for (1) and else itr++; for (2). (c) itr < vec.end() for (1) and itr++; for (2). (c) itr <= vec.end() for (1) and itr++; for (2).