在Java中对双链接列表进行排序
我必须为我的编程课制作一个链表程序。它可以工作,每次插入一个数字时,它都会放在列表的开头。现在,我的老师要我们使用链表程序,按升序对数字进行排序。我完全不知道该怎么做。谁能给我指出正确的方向吗? 以下是我的列表代码:在Java中对双链接列表进行排序,java,list,sorting,Java,List,Sorting,我必须为我的编程课制作一个链表程序。它可以工作,每次插入一个数字时,它都会放在列表的开头。现在,我的老师要我们使用链表程序,按升序对数字进行排序。我完全不知道该怎么做。谁能给我指出正确的方向吗? 以下是我的列表代码: public class SortedList { private DoubleNode head = null; private int listLength; public static void main(String[] args) { SortedList l
public class SortedList {
private DoubleNode head = null;
private int listLength;
public static void main(String[] args) {
SortedList list = new SortedList();
list.insert(6);
list.insert(7);
System.out.println(list.toString());
}
public void insert(double value) {
head = new DoubleNode(value, head);
listLength++;
}
public String toString() {
String answer = "[ ";
for (DoubleNode current = head; current != null; current = current
.getLink()) {
answer += current.getData() + " ";
}
answer += "]";
return answer;
}
public int find(double value) {
if (listLength == 0)
return -1;
int pos = 1;
for (DoubleNode current = head; current != null; current = current.getLink()) {
if (current.getData() == value)
return pos;
pos++;
}
return -1;
}
public int size() {
return listLength;
}
public boolean removeAt(int index) {
if (index < 1 || index > listLength)
return false;
if (index == 1) {
if (head != null) {
head = head.getLink();
listLength--;
}
return true;
}
DoubleNode current = head;
for (int i = 1; i < (index - 1); i++) {
if (current.getLink() == null)
return false;
current = current.getLink();
}
current.setLink(current.getLink().getLink());
listLength--;
return true;
}
想法 1) 在最简单的情况下,列表已排序: ->A
2)现在,考虑“下一个”案例(即,你在1个新元素中添加1个大小的列表)
->A[现在,我将尝试添加C] 您只需检查C是否大于A,在这种情况下,您可以在末尾添加“C”(->A->C) 3) 我们可以概括案例(2):在任何后续案例中,您都必须遍历列表,直到“看到”一个新节点,该节点大于您要插入的节点 ->A->C[添加B]检查1:A(B>A)
检查2:C(B
这意味着我们可以按如下方式替换链接:
用两个新链接替换A->C,一个来自A->B,另一个来自B->C
以这种方式插入以确保列表保持排序
具体地说
因此,您必须修改应用程序的insert(…)方法,从列表开始,检查每个DoubleNode,向下走,并“记住”,即存储前一个DoubleNode,直到它到达列表的末尾,或者它看到最后一个节点<新节点,当前节点大于新节点 @你的老师提到一些书了吗?请读一下。另外,开始编写单元测试。在代码中发布更多注释!使用一些基本的排序算法,如插入或选择少量记录,检查比较器接口,以及我的老师说,她教我们链表的方式与我们的书教链表的方式不同。谢谢你的回答…尽管这是多年前的事了!
// File: DoubleNode.java based on the DoubleNode class by Michael Main
/**************************************************************************
* DoubleNode provides a node for a linked list with double data in each node.
*
* @note
* Lists of nodes can be made of any length, limited only by the amount of
* free memory in the heap.
*
* @author Michael Main
* shortened by Beth Katz and Stephanie Elzer to be only the basics
*
* @version
* February 2007
***************************************************************************/
public class DoubleNode
{
// Invariant of the DoubleNode class:
// 1. The node's double data is in the instance variable data.
// 2. For the final node of a list, the link part is null.
// Otherwise, the link part is a reference to the next node of the list.
private double data;
private DoubleNode link;
/**
* Initialize a node with a specified initial data and link to the next
* node. Note that the initialLink may be the null reference, which
* indicates that the new node has nothing after it.
* @param initialData
* the initial data of this new node
* @param initialLink
* a reference to the node after this new node--this reference may be
* null to indicate that there is no node after this new node.
* @postcondition
* This node contains the specified data and link to the next node.
**/
public DoubleNode(double initialData, DoubleNode initialLink)
{
data = initialData;
link = initialLink;
}
/**
* Accessor method to get the data from this node.
* @param - none
* @return
* the data from this node
**/
public double getData( )
{
return data;
}
/**
* Accessor method to get a reference to the next node after this node.
* @param - none
* @return
* a reference to the node after this node (or the null reference if
* there is nothing after this node)
**/
public DoubleNode getLink( )
{
return link;
}
/**
* Modification method to set the data in this node.
* @param newData
* the new data to place in this node
* @postcondition
* The data of this node has been set to newData.
**/
public void setData(double newData)
{
data = newData;
}
/**
* Modification method to set the link to the next node after this node.
* @param newLink
* a reference to the node that should appear after this node in the
* linked list (or the null reference if there is no node after this node)
* @postcondition
* The link to the node after this node has been set to newLink. Any other
* node (that used to be in this link) is no longer connected to this node.
**/
public void setLink(DoubleNode newLink)
{
link = newLink;
}
}
check 1: A (B > A)
check 2: C (B < C) !