有头结点的链表如何置空用代码举例

如果链表有头结点，则可以将头结点的next指针置空即可将整个链表置空。下面是一个示例代码：

class ListNode:
    def __init__(self, val=0, next=None):
        self.val = val
        self.next = next

def clearLinkedList(head):
    head.next = None

# 创建一个有头结点的链表
head = ListNode(-1)
node1 = ListNode(1)
node2 = ListNode(2)
node3 = ListNode(3)
head.next = node1
node1.next = node2
node2.next = node3

# 置空链表
clearLinkedList(head)

# 验证链表是否为空
if head.next is None:
    print("链表已被置空")
else:
    print("链表不为空")

输出结果为：链表已被置空。