用stl map时直接insert，提高效率，不需要先find，再insert

 

map::insert() will only create:

using std::cout; using std::endl;  typedef std::map<int, std::string> MyMap;  MyMap map;  // ...  std::pair<MyMap::iterator, bool> res = map.insert(std::make_pair(key,value));  if ( ! res.second ) {      cout << "key " <<  key << " already exists "           << " with value " << (res.first)->second << endl;  } else {      cout << "created key " << key << " with value " << value << endl;  }  

For most of my apps, I usually don't care if I'm creating or replacing, so I use the easier to read map[key] = value.