<p>what is a good way to select a random element from a map?  C++.  It is my understanding that maps don't have random access iterators.  The key is a long long and the map is sparsely populated.  </p>

```
```
map<...> MyMap;
iterator item = MyMap.begin();
std::advance( item, random_0_to_n(MyMap.size()) );
```
```