列表转链表,再双指针

class node:
    def __init__(self, data):
        self.val = data
        self.next = None
        
class Solution:
    def __init__(self):
        self.li=[i for i in range(1,8)]
        
    def get_ans(self,k):
        self.head=node(self.li[0])
        temp=self.head
        for i in self.li[1:]:
            i=node(i)
            temp.next=i
            temp=temp.next
        left,right=self.head,self.head
        for _ in range(k):
            right=right.next
        while right:
            left=left.next
            right=right.next
        return left.val
        
if __name__=="__main__":
    k=int(input())
    ans=Solution()
    print(ans.get_ans(k)) js