在Scala中创建参数化图形类型

class Graph[T](nodes: Set[T], edges: Set[(T, T)]) {
  def addNode(node: T): Graph[T] = new Graph(nodes + node, edges)

  def addEdge(edge: (T, T)): Graph[T] = new Graph(nodes, edges + edge)

  def neighbors(node: T): Set[T] = edges.filter(_._1 == node).map(_._2)

  def hasPath(start: T, end: T): Boolean = {
    def dfs(visited: Set[T], current: T): Boolean = {
      if (visited.contains(current)) false
      else if (current == end) true
      else {
        val newVisited = visited + current
        neighbors(current).exists(dfs(newVisited, _))
      }
    }

    dfs(Set.empty, start)
  }
}

val intGraph = new Graph[Int](Set(1, 2, 3), Set((1, 2), (2, 3)))

val stringGraph = new Graph[String](Set("A", "B", "C"), Set(("A", "B"), ("B", "C")))