# class ListNode: # def __init__(self, x): # self.val = x # self.next = None # # # @param head ListNode类 # @param k int整型 # @return ListNode类 # class Solution: def reverseKGroup(self , head , k ): # write code here def reverse(a, b): prev, curr, nxt = None, a, a while curr!=b: nxt = curr.next curr.next = prev prev = curr curr = nxt return prev a, b = head, head for i in range(k): if not b: return head b = b.next newHead = reverse(a, b) a.next = self.reverseKGroup(b, k) return newHead