Basics of Swift

Herein, I have covered topics from -

1. Arrays, Set, enum
2. Closures, trailing closure
3. Functions and Class
4. Error Handling
5. Use of struct
6. Option chaining and nil coalescing
7. Use of static, guard and mutating keyword
8. Understanding 'extension' and modifying it

Tried to build Byte Pair Encoding (BPE) from scratch for tokenization. Inspiration from karpathy