leetcode.

LongestAbsoluteFilePath.scala

import scala.collection.mutable.ListBuffer

/**
  * Created by User on 10/28/2016.
  */
object LongestAbsoluteFilePath {

  class Node(val name: String, val depth: Int) {

    val nodeType: NodeType.Value = getNodeType(name)

    val subNodes = new ListBuffer[Node]

    def addNode(node: Node) = subNodes += node

    def addNodes(nodes: List[Node]) = subNodes.appendAll(nodes)

    override def toString = s"Node(nodeType=$nodeType, name=$name, depth=$depth)"
  }

  object NodeType extends Enumeration {
    val File, Dir = Value
  }

  def parse(input: String): Option[Node] = {
    val strs = input.split("\n")
    if (strs.isEmpty) {
      Option.empty
    }
    else {
      val headName = strs.head
      var depth = 0
      val root = new Node(headName, depth)
      val tail = strs.tail
      if (tail.isEmpty) {
        Option(root)
      }
      else {
        val stack = new java.util.Stack[Node]()
        stack.push(root)
        for (nodeStr <- tail) {
          val node = getNode(nodeStr)
          val parent = if (node.depth > depth) {
            stack.peek()
          }
          else {
            while (stack.peek().depth != node.depth - 1) {
              stack.pop()
            }
            stack.peek()
          }
          parent.addNode(node)
          stack.push(node)
          depth = node.depth
        }
        Option(root)
      }
    }
  }

  /**
    *
    * @param nodeStr
    * @return depth -> nodeName
    */
  def getNode(nodeStr: String): Node = {
    var tabCount = 0
    var tail = nodeStr
    while (tail.contains("\t")) {
      tabCount += 1
      tail = tail.substring(1)
    }
    new Node(tail, tabCount)
  }

  def getLongestLength(input: String): Int = {
    parse(input) match {
      case Some(node) => 2
      case None => 0
    }
  }

  def getNodeType(name: String): NodeType.Value = {
    if (name.contains('.')) NodeType.File else NodeType.Dir
  }

  def main(args: Array[String]): Unit = {
    val input = "dir\n\tsubdir1\n\t\tsubsubdir1\n\t\t\tfile1.ext\n\tsubdir2\n\tsubdir3\n\t\tsubsubdir2\n\t\t\tfile2.ext"
    println(input)
    val node = parse(input)
    println(node)
  }

}