我试图找到如何使用inBetween作为公共方法来获取列表中的数字。
DoubleLinked类：
public class DoublyLinkedList
{
private Link first; // ref to first item
private Link last; // ref to last item
// -------------------------------------------------------------
public DoublyLinkedList() // constructor
{
first = null; // no items on list yet
last = null;
}
// -------------------------------------------------------------
public boolean isEmpty() // true if no links
{ return first==null; }
// -------------------------------------------------------------
public void insertFirst(long dd) // insert at front of list
{
Link newLink = new Link(dd); // make new link
if( isEmpty() ) // if empty list,
last = newLink; // newLink <-- last
else
first.previous = newLink; // newLink <-- old first
newLink.next = first; // newLink --> old first
first = newLink; // first --> newLink
}
// -------------------------------------------------------------
public void insertLast(long dd) // insert at end of list
{
Link newLink = new Link(dd); // make new link
if( isEmpty() ) // if empty list,
first = newLink; // first --> newLink
else
{
last.next = newLink; // old last --> newLink
newLink.previous = last; // old last <-- newLink
}
last = newLink; // newLink <-- last
}
// -------------------------------------------------------------
public Link deleteFirst() // delete first link
{ // (assumes non-empty list)
Link temp = first;
if(first.next == null) // if only one item
last = null; // null <-- last
else
first.next.previous = null; // null <-- old next
first = first.next; // first --> old next
return temp;
}
// -------------------------------------------------------------
public Link deleteLast() // delete last link
{ // (assumes non-empty list)
Link temp = last;
if(first.next == null) // if only one item
first = null; // first --> null
else
last.previous.next = null; // old previous --> null
last = last.previous; // old previous <-- last
return temp;
}
// -------------------------------------------------------------
// insert dd just after key
public boolean insertAfter(long key, long dd)
{ // (assumes non-empty list)
Link current = first; // start at beginning
while(current.dData != key) // until match is found,
{
current = current.next; // move to next link
if(current == null)
return false; // didn't find it
}
Link newLink = new Link(dd); // make new link
if(current==last) // if last link,
{
newLink.next = null; // newLink --> null
last = newLink; // newLink <-- last
}
else // not last link,
{
newLink.next = current.next; // newLink --> old next
// newLink <-- old next
current.next.previous = newLink;
}
newLink.previous = current; // old current <-- newLink
current.next = newLink; // old current --> newLink
return true; // found it, did insertion
}
// -------------------------------------------------------------
public Link deleteKey(long key) // delete item w/ given key
{ // (assumes non-empty list)
Link current = first; // start at beginning
while(current.dData != key) // until match is found,
{
current = current.next; // move to next link
if(current == null)
return null; // didn't find it
}
if(current==first) // found it; first item?
first = current.next; // first --> old next
else // not first
// old previous --> old next
current.previous.next = current.next;
if(current==last) // last item?
last = current.previous; // old previous <-- last
else // not last
// old previous <-- old next
current.next.previous = current.previous;
return current; // return value
}
// -------------------------------------------------------------
public void displayForward()
{
System.out.print("List (first-->last): ");
Link current = first; // start at beginning
while(current != null) // until end of list,
{
current.displayLink(); // display data
current = current.next; // move to next link
}
System.out.println("");
}
// -------------------------------------------------------------
public void displayBackward()
{
System.out.print("List (last-->first): ");
Link current = last; // start at end
while(current != null) // until start of list,
{
current.displayLink(); // display data
current = current.previous; // move to previous link
}
System.out.println("");
}
// -------------------------------------------------------------
} // end class DoublyLinkedList
InBetweenDemo Class作为Main类：
public class InBetweenDemo
{
public static void main(String[] args)
{ // make a new list
DoublyLinkedList theList = new DoublyLinkedList();
theList.insertFirst(22); // insert at front
theList.insertFirst(44);
theList.insertFirst(66);
theList.insertLast(11); // insert at rear
theList.insertLast(33);
theList.insertLast(55);
theList.displayForward();
int n=55;// display list forward
System.out.println("inBetween("+n+") "+ theList.inBetween(n));
theList.deleteFirst(); // delete first item
theList.displayForward();
n=55;
System.out.println("inBetween("+n+") "+ theList.inBetween(n));
theList.deleteLast();
theList.displayForward();
n=33;
System.out.println("inBetween("+n+") "+ theList.inBetween(n));
theList.deleteKey(22); // delete item with key 11
theList.displayForward();
System.out.println("inBetween("+n+") "+ theList.inBetween(n));
n=99;
System.out.println("inBetween("+n+") "+ theList.inBetween(n));
theList.displayForward(); // display list forward
theList.insertAfter(11, 77); // insert 77 after 22
theList.insertAfter(33, 88); // insert 88 after 33
theList.displayForward(); // display list forward
} // end main()
} // end class DoublyLinkedApp
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我计划使用inBetween方法接受一个项作为其参数，如果该项位于该列表中最小和最大元素之间，则返回true。否则，该方法返回false。但是我不知道如何在代码中编写它。此外，我想知道如果项目是否在列表中删除最小项目或列表中删除了最大项目，程序可能不知道哪个项目是最大和最小的。那么我是否还应该使用一种方法来获得最大值和最小值？
您可以创建inBetween方法，使其将数字作为参数，并在内部调用一个方法，您将在该方法中实现确定列表中最小值和最大值的算法。注意这仅在您的列表是全局定义而不是特定方法时才有效，否则您必须将列表作为参数提供给inBetween方法。所以在伪代码中你可以这样做：
inBetween(numberToBeChecked):
max = getMax(yourList)
min = getMin(yourList) // you can implement this in one method and return an array containing of two elements for example. It's your choice.
if (numberToBeChecked > min && numberToBeChecked < max):
return True
else:
return False
希望这可以帮助。