python-leetcode面试题解之第25题K个一组翻转链表-python题解.zip

# Definition for singly-linked list. # class ListNode(object): # def __init__(self, x): # self.val = x # self.next = None # class Solution(object): # def reverseKGroup(self, head, k): # """ # :type head: ListNode # :type k: int # :rtype: ListNode # """ class Solution(object): def reverseKGroup(self, head, k): if head is None: return None index = 0 lead, last = 0, 0 pos = head temp = ListNode(-1) temp.next = head head = temp start = head while pos is not None: if index % k == k - 1: last = pos.next start = self.reverseList(start, last) pos = start pos = pos.next index += 1 return head.next def reverseList(self, head, end): pos = head.next last = end next_start = pos while pos != end: head.next = pos last_pos = pos pos = pos.next last_pos.next = last last = last_pos return next_start