JAVA空指针异常问题
0
悬赏园豆：20
[已解决问题]
解决于 2018-04-17 10:57
public class DeleteMin<T> { @SuppressWarnings({ "unchecked", "rawtypes", "hiding" }) public static <T extends Comparable> void deleteMin(linkList<T> La) { if (La.isEmpty()) { System.out.println("链表为空表"); } Node<T> p,q; p = La.getHead(); q = La.getHead().next; while (q != null) { for (int i = 0; i < La.size(); i++) { if (p.data.compareTo(q.data) <= 0) { q = q.next; } p = q; } p.next = p.next.next; } } public static void main(String[] args) { int [] arr={12,23,35,49,56}; linkList<Integer> La = new linkList<Integer>(); for (int i = 0; i < arr.length; i++) La.add(arr[i], i + 1); System.out.println("单链表arr中数据元素为："); La.nextOrder(); deleteMin(La); System.out.println("单链表arr中数据元素为："); La.nextOrder(); //de.deleteMin(head); } }
带头节点的单链表中删除最小值结点
if语句报空指针异常
Exception in thread "main" java.lang.NullPointerException
问题补充：
@SuppressWarnings({ "unchecked", "rawtypes", "hiding" })
public static <T extends Comparable> void deleteMin(linkList<T> La) {
if (La.isEmpty()) {
System.out.println("链表为空表");
}
Node<T> p,q,k,w;
k = La.getHead();
w = La.getHead();
p = La.getHead().next;
q = La.getHead().next.next;
while (q != null) {
for (int i = 0; i < La.size()-1; i++) {
if (p.data.compareTo(q.data) <= 0) {
w = w.next;
q = q.next;
} else {
k = p;
p = q;
q = q.next;
w = w.next;
}
}
}
if (k.next == p) {
k.next = p.next;
} else {
w.next = p.next;
}
}
因为前面找到了最小值节点但是由于是单链表没有前驱所有很难搞。我用四个指针完成了，这是删除算法，各位大佬能不能帮我优化一下，
最佳答案
0
@SuppressWarnings({ "unchecked", "rawtypes", "hiding" })
public static <T extends Comparable> void deleteMin(linkList<T> La) {
if (La.isEmpty()) {
System.out.println("链表为空表");
}
Node<T> p, q;
p = La.getHead().next;
T Min = p.data;
while (p != null) {
if (p.data.compareTo(Min) <= 0) {
Min = p.data;
}
p = p.next;
}
p = La.getHead();
q = La.getHead().next;
while (q != null) {
if (q.data.compareTo(Min) == 0) {
p.next = q.next;
break;
} else {
p = q;
q = q.next;
}
}
}
其他回答(1)
0
p.next.next p.next这个操作是否为空
收获园豆：20
谢谢你
