Functional Programming Principles in Scala => Functional Sets

Signed-off-by: CyberZHG <443442708@qq.com>
Functional Programming Principles in Scala => Object-Oriented Sets

Signed-off-by: CyberZHG <443442708@qq.com>
Functional Programming Principles in Scala => Huffman Coding

Signed-off-by: CyberZHG <443442708@qq.com>
Merge branch 'Functional_Programming_Principles_in_Scala'