problem107.pi

import util.
import ordset.

main =>
  Lines = map(split_string, read_file_lines("./files/p107_network.txt")),
  TotalCost = get_total_cost(Lines),
  get_optimized_cost(Lines, OptimizedCost),
  println(TotalCost - OptimizedCost).
  println("Hello\n").

get_total_cost(Xs) = sum(map(nils_to_zero, flatten(Xs))) // 2.

get_optimized_cost(Xs, Result) =>
  Lines = map(to_array, Xs).to_array,
  Optimized = 0,
  Adjoined = new_ordset([1]),
  foreach(I in 1..(length(Lines)-1))
    Candidate = nil,
    CandidateVertex = nil,
    foreach(J in 1..length(Lines))
      if member(J, Adjoined) then
        Line = Lines[J],
        foreach(K in 1..length(Lines))
          if Line[K] != nil && not member(K, Adjoined) then
            if Candidate == nil || Candidate > Line[K] then
              Candidate := Line[K],
              CandidateVertex := K
            end
          end
        end
      end
    end,
    Adjoined := insert(Adjoined, CandidateVertex),
    Optimized := Optimized + Candidate
  end,
  Result = Optimized.

sum(Xs) = fold((+), 0, Xs).

split_string(S) = map(term_to_int, S.split(",")).

term_to_int("-") = nil.
term_to_int(S) = to_int(S).

nils_to_zero(nil) = 0.
nils_to_zero(X) = X.