試圖弄清楚如何對雙向鏈表進行排序。 我在這裏得到一個空指針異常:雙向鏈表的排序方法
while (temp.getNext()!=null){
是否有更好的方法或任何意見,得到這個去的路嗎?
public void sort() {
//bubble sort!
boolean swapped = (head != null);
while (swapped) {
swapped = false;
EntryNode temp = head;
//can't swap something with nothing
while (temp.getNext()!=null){
if (temp.getLastName().compareTo(temp.getNext().getLastName()) > 0) {
swapped = true;
//special case for two nodes
if (size == 2) {
//reassign head and tail
tail = temp;
head = temp.getNext();
tail.setPrev(head);
head.setNext(tail);
tail.setNext(null);
head.setNext(null);
}
//if swapping is at head
else {
if (temp == head) {
head = temp.getNext();
temp.setNext(head.getNext());
head.getNext().setPrev(temp);
head.setPrev(null);
head.setNext(temp);
temp.setPrev(head);
}
else {
temp.setNext(temp.getNext().getNext());
temp.setPrev(temp.getNext());
temp.getNext().setNext(temp);
temp.getNext().setPrev(temp.getPrev());
}
}
}
//loop through list
temp = temp.getNext();
}
}
}
這必須是功課。你不要在現實世界中對鏈表進行排序。 – EJP 2012-03-14 02:49:33
@EJP在基於LISP的語言中,您始終對鏈表進行排序 – 2012-03-14 03:04:00