Random element in a map

Question

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

Answer 1

If your map is static, then instead of a map, use a vector to store your key/value pairs in key order, binary search to look up values in log(n) time, and the vector index to get random pairs in constant time. You can wrap the vector/binary search to look like a map with a random access feature.