Haskell数据类型过滤子列表列表

Question

I got a person data type that has a name and their weight looks like below.

data Person = Person
    {pName :: String,
     pWeight :: Double} deriving (Show)

persons :: [Person]
persons = [Person "Peter" 35.0,
            Person "Joe" 45.0,
            Person "Alex" 55.0,
            Person "Ruby" 60.0,
            Person "John" 65.0,
            Person "Ann" 35.0]

Q1 If I want to filter and get the first sub set from the given persons list that their maximum weights sum is to be less than a given value how to do it?

eg Output if maximum Weight is 150.0

Person "Peter" 35.0

Person "Joe" 45.0

Person "Alex" 55.0

Total weight : 135.0

Q2 If I want to get all the subsets of a maximum weight that is set

eg Output if max weight is 100.0

Set 1

Person "Peter" 35.0 Person "Joe" 45.0

Total weight : 80.0

Set 2

Person "Alex" 55.0

Total weight : 55.0

Set 3 ...... so on

Answer 1

The first can be done using a filter. The second seems like a knapsack problem. In which case you can search for strategies to solve it. If you run into any issues after you write your code, please re-post here and the community will be glad to help.