sparsehash 2.0.4 Memory-efficient hashtable implementations
This library contains several hash-map implementations, similar in API to SGI's
hash_map class, but with different performance characteristics.
sparse_hash_map uses very little space overhead, 1-2 bits per entry.
dense_hash_map is very fast, particularly on lookup.
dense_hash_set are the set versions of these routines. All these implementation use a hashtable with internal quadratic probing. This method is space-efficient -- there is no pointer overhead -- and time-efficient for good hash functions.