   Simple question about data structures...
  Is C++ STL map is basically same as hash table?   
  No, a STL map (and set) is a red-black tree, which means most operations are O(log(N)).If you want a hash map, you can use std::unordered_map and std::unordered_set if your compiler supports the C++0x standard. Most compilers provide their own hash map extensions as well.   ;  any idea where i can read about this O(log(N)), because I all time wanted to learn this?   ;  The term to Google would be "big O notation".It describes a function in terms of its worst case running time for size N. N is the number of iteams involved, it might be the number of items to sort for std::sort(), in this case it is the number of elements in the std::map<>.   