hhc-tsp/src/main/scala/Main.scala

import model.Coord
import model.Customer
import model.HHCEdge
import scala.collection.mutable._
object Main {
  def main(args: Array[String]): Unit = {

    val coord1 = Coord(3, 4)
    println(s"Distance from origin = ${coord1.distance}")

    val cust1 = Customer(coord1, 5)
    val cust2 = Customer(Coord(2, 5), 7)

    println(s"Customer 1 = ${cust1}")
    println(s"Customer 2 = ${cust2}")

    val cust3 = Customer(Coord(3, 5), 6)
    val cust4 = Customer(Coord(6, 8), 9)
    val cust5 = Customer(Coord(5, 4), 6)

    val edge1 = HHCEdge(cust1, cust2)
    val edge2 = HHCEdge(cust3, cust4)

    println(s"Edge 1 = ${edge1}")
    println(s"Edge 1 weight = ${edge1.weight}")

    val V = Array(cust1, cust2, cust3, cust4, cust5)

    val E = Array(edge1, edge2)

    V.foreach(println(_))
    // prints
    // Customer(Coord(3, 4), 5)
    // Customer(Coord(2, 5), 7)
    // Customer(Coord(3, 5), 6)
    // Customer(Coord(6, 8), 9)
    // Customer(Coord(5, 4), 6)
    E.foreach(println(_))
    //prints
    // HHCEdge(Customer(Coord(3, 4), 5), Customer(Coord(2, 5), 7))
    // HHCEdge(Customer(Coord(3, 5), 6), Customer(Coord(6, 8), 9))

    // sample adjacency
    // format: off
    val edges = Array(
        Array(0 , 9 , 75, 0 , 0),
        Array(9 , 0 , 95, 19, 42),
        Array(75, 95, 0 , 51, 66),
        Array(0 , 19, 51, 0 , 31),
        Array(0 , 42, 66, 31, 0)
    );

    //format: on

    // Prim's algorithm

    val selected: ArrayBuffer[Boolean] =
      ArrayBuffer.from(Array.ofDim[Boolean](5).toIndexedSeq)

    selected(0) = true

    var numberOfEdges = 0

    for (_ <- numberOfEdges to 3) {
      var min = 999999
      var x = 0
      var y = 0
      for (i <- 0 to 4) {
        if (selected(i) == true) {
          for (j <- 0 to 4) {
            if (selected(j) == false && edges(i)(j) != 0) {
              if (min > edges(i)(j)) {
                min = edges(i)(j)
                x = i
                y = j
              }
            }
          }
        }
      }
      println(s"Edge selected $x - $y : ${edges(x)(y)}")
      selected(y) = true
    }

    // Prim's algorithm result
    // Edge selected 0 - 1: 9
    // Edge selected 1 - 3: 19
    // Edge selected 3 - 4: 31
    // Edge selected 3 - 2: 51

    // Verify the result with the one at https://www.programiz.com/dsa/prim-algorithm

    val edges2: ArrayBuffer[ArrayBuffer[Double]] = ArrayBuffer.empty

    // create adjacency matrix from given customers
    for (i <- 0 to 4) {
      edges2.append(ArrayBuffer.empty)
      for (j <- 0 to 4) {
        edges2(i).append(HHCEdge(V(i), V(j)).weight)
      }
    }

    println(edges2) // prints adjacency matrix

    // ArrayBuffer(
    //   ArrayBuffer(0.0               , 1.4142135623730951, 1.0              , 5.0              , 2.0),
    //   ArrayBuffer(1.4142135623730951, 0.0               , 1.0              , 5.0              , 3.1622776601683795),
    //   ArrayBuffer(1.0               , 1.0               , 0.0              , 4.242640687119285, 2.23606797749979),
    //   ArrayBuffer(5.0               , 5.0               , 4.242640687119285, 0.0              , 4.123105625617661),
    //   ArrayBuffer(2.0               , 3.1622776601683795, 2.23606797749979 , 4.123105625617661, 0.0),
    // )

  }
}