Add HashSmith to Data Structures

Author: bluuewhale

README.md

@@ -329,6 +329,7 @@ _Efficient and specific data structures._
 - [Apache Parquet](https://parquet.apache.org) - Columnar storage format based on assembly algorithms from Google's paper on Dremel.
 - [Apache Thrift](https://thrift.apache.org) - Data interchange format that originated at Facebook.
 - [Big Queue](https://github.com/bulldog2011/bigqueue) - Fast and persistent queue based on memory-mapped files.
+- [HashSmith](https://github.com/bluuewhale/hash-smith) - Hash map and set implementations using SwissTable-style SWAR/SIMD control-byte probing, optimized for memory efficiency.
 - [Persistent Collection](https://github.com/hrldcpr/pcollections) - Persistent and immutable analogue of the Java Collections Framework.
 - [Protobuf](https://github.com/protocolbuffers/protobuf) - Google's data interchange format.
 - [RoaringBitmap](https://github.com/RoaringBitmap/RoaringBitmap) - Fast and efficient compressed bitmap.