# class ListNode:# def __init__(self, x):# self.val = x# self.next = NoneclassSolution:defFindKthToTail(self , pHead , k ):ifnot pHead:returnNone
left, right = pHead, pHead
while right and k >0:
right = right.next
k -=1if k >0:returnNonewhile right:
left = left.next
right = right.nextreturn left