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find and insert after

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ivan 2018-12-14 17:25:42 +08:00
parent 1a1e7e06b3
commit fe3c0a3592
2 changed files with 57 additions and 9 deletions
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33
scala/src/main/scala/ch06_linkedlist/SinglyLinkedList.scala
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@ -10,11 +10,19 @@ class SinglyLinkedList(var headOpt: Option[Node]) {
def findByValue(value: Int): Option[Node] = {
None
}
headOpt.flatMap(head => {
var node = head
while (!node.data.equals(value) && node.next.nonEmpty) {
node = node.next.get
}
def findByIndex(index: Int): Option[Node] = {
None
if (node.data.equals(value)) {
return Some(node)
} else {
//arrive the end of the chain
return None
}
})
}
def insertToHead(value: Int): Unit = {
@ -55,9 +63,22 @@ class SinglyLinkedList(var headOpt: Option[Node]) {
}
}
def insertAfter(existNode: Node, value: Int) = {}
def insertAfter(existNode: Node, value: Int): Unit = {
val newNode = new Node(value, None)
insertAfter(existNode, newNode)
}
def insertAfter(existNode: Node, newNode: Node) = {}
def insertAfter(existNode: Node, newNode: Node): Unit = {
existNode.next match {
case None =>
//exist node is tail
newNode.next = None
existNode.next = Some(newNode)
case Some(next) =>
newNode.next = Some(next)
existNode.next = Some(newNode)
}
}
def insertBefore(existNode: Node, value: Int) = {}

33
scala/src/test/scala/ch06_linkedlist/SinglyLinkedListTest.scala
View File

@ -2,12 +2,12 @@ package ch06_linkedlist
import org.scalatest.{FlatSpec, Matchers}
class SinglyLinkedListTest extends FlatSpec with Matchers{
class SinglyLinkedListTest extends FlatSpec with Matchers {
behavior of "SinglyLinkedListTest"
it should "insertToHead for new values" in {
val list:SinglyLinkedList = new SinglyLinkedList()
val list: SinglyLinkedList = new SinglyLinkedList()
list.insertToHead(0)
list.insertToHead(1)
@ -19,7 +19,7 @@ class SinglyLinkedListTest extends FlatSpec with Matchers{
}
it should "insertTail for new values" in {
val list:SinglyLinkedList = new SinglyLinkedList()
val list: SinglyLinkedList = new SinglyLinkedList()
list.insertTail(0)
list.insertTail(1)
@ -30,4 +30,31 @@ class SinglyLinkedListTest extends FlatSpec with Matchers{
}
it should "find by value" in {
val list: SinglyLinkedList = new SinglyLinkedList()
list.insertTail(0)
list.insertTail(1)
list.insertTail(2)
list.insertTail(3)
list.mkString() should equal("0123")
val node1 = list.findByValue(1).get
node1.next.get.data should equal(2)
}
it should "insert after node and can find it back" in {
val list: SinglyLinkedList = new SinglyLinkedList()
list.insertTail(0)
list.insertTail(1)
list.insertTail(3)
list.insertTail(4)
val node1 = list.findByValue(1).get
list.insertAfter(node1,2)
list.mkString() should equal("01234")
}
}