I dont know i only looked at two questions.

If you have a good knowledge of C++, algorithms, data structures and a reasonable level of intelligence and motivation then you should be fine.

Research any areas you feel weak in. You mentioned you have no knowledge of tree structures. You should have a fair knowledge at least of A* and dijkstra's algorithm. These will be useful in any sort of pathfinding based on cost type question. Maybe get an algorithms book such as those by Robert Sedgewick and practice every data structure/algorithm shown until you are intimately familiar with both the algos and their applicability. Try to solve old question papers. Thats probably the best way to prepare.