目录
思路分析
这个题目也没有什么很好的解决方法.
首先先遍历一次链表,求出这个链表的长度n.
倒数第k个,其实就是正数n-k+1个.
cpp
/**
* Definition for singly-linked list.
* struct ListNode {
* int val;
* ListNode *next;
* ListNode(int x) : val(x), next(NULL) {}
* };
*/
class Solution {
public:
ListNode* getKthFromEnd(ListNode* head, int k) {
ListNode* p = head;
int len=0;
while(p){
len++;
p=p->next;
}
if(k>len)return NULL;
p = head;
k = len-k+1;
for(int i=1;i<k;i++){
p = p->next;
}
return p;
}
};
python
# Definition for singly-linked list.
# class ListNode:
# def __init__(self, x):
# self.val = x
# self.next = None
class Solution:
def getKthFromEnd(self, head: ListNode, k: int) -> ListNode:
p = head
len = 0
while p:
len+=1
p = p.next;
if k>len:return None
k = len - k + 1
p = head
for i in range(1,k):
p = p.next
return p