CODEWITHSUNDEEP
scalagraph
Teodorico Levoff
Teodorico Levoff

Reputation: 1659

Representing a graph in Scala as a Adjacency list

An adjacency list representation as a graph is shown here,

https://www.khanacademy.org/computing/computer-science/algorithms/graph-representation/a/representing-graphs.

I am fairly new to Scala, and so this is fairly trivial I am assuming. I want to represent my graph in Scala as an adjacency list but edges should have a weight. So I was thinking having a tuple for each entry in the adjacency list for each vertex, where the tuple is the vertex and the edge cost. Hopefully this makes sense. I just want to know how to write this graph representation to a val.

For example: 

A -> [(B, 1), (C, 1), (D, 1)]

B -> [(A, 1), (C, 2), (D, 2)]

C -> [(A, 1), (B, 2)]

D -> [(A, 1), (B, 2)]

How would I write this as a val in Scala? The index of the list can represent the letters of the nodes. Would this be a List[List[(String, Int)]]? I find it hard in Scala to assign values to variables when I really want to specify the type of the variable.

Upvotes: 0

Views: 851

Answers (1)

Brian
Brian

Reputation: 20285

How would I write this as a val in Scala?

val adjList = List(List(("b", 1), ("c", 1), ("d", 1)), List(...), List(...), List(...))

The types are inferred for your to be List[List[(String, Int)]]. You can manually specify them if you wish but it is not required.

Upvotes: 0

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