You are given two scala source code files:

a$.$ StreamOperation.scala

i$.$ Sample functional programming code for map, filter, reduce

ii$.$ TODO sections: provide your implementation of some functions. You must implement

these functions according to the comment section above each function signature, also

refer to the function body comments for implementation hints. You must NOT change

other parts of the source code.

b$.$ Main.scala

i$.$ Testing code for debugging. You may want to write more code to test your

implementation, particularly to use a good combination of different inputs $($see comments $/$

hints in the StreamOperation.scala and Main.scala$).$