求链式表的倒数第k项的地址,的代码
时间: 2024-09-22 19:07:22 浏览: 16
在链表中求倒数第k项的地址通常涉及双指针技术,一种常见的解决方案是在Python中使用如下的步骤:
```python
class ListNode:
def __init__(self, val=0, next=None):
self.val = val
self.next = next
def find_kth_to_last(head, k):
# 使用快慢指针
slow = fast = head
for _ in range(k): # 快速指针先向前移动k步
if fast is not None:
fast = fast.next
while fast is not None: # 当快速指针到达结尾时,慢速指针正好指向倒数第k个元素
slow = slow.next
fast = fast.next
return slow # 返回倒数第k个节点的地址,如果k越界则返回None
# 示例:
# 创建一个链表: 1 -> 2 -> 3 -> 4 -> 5
head = ListNode(1)
head.next = ListNode(2)
head.next.next = ListNode(3)
head.next.next.next = ListNode(4)
head.next.next.next.next = ListNode(5)
k = 2 # 要查找的倒数位置
address = find_kth_to_last(head, k) # address now contains the address of the second-to-last node (4), or None if k is out of bounds
```