unordered-containers-0.2.20: Efficient hashing-based container types

Efficient hashing-based container types. The containers have been optimized for performance critical use, both in terms of large data quantities and high speed.

The declared cost of each operation is either worst-case or amortized, but remains valid even if structures are shared.

Security

This package currently provides no defenses against hash collision attacks such as HashDoS. Users who need to store input from untrusted sources are advised to use Data.Map or Data.Set from the containers package instead.