We’re going to use TMap instead of std::map, because we’re writing Unreal standard C++. Unreal has its own data types that override the standard libraries, because they’re more suited to the sort of platforms that we’re going to deploy on, when we make games in Unreal.
#include <map> #define TMap std::map
std::unordered_set or Unreal TSet is a valid alternative. Map is a more versatile.