题解 | #链表中的节点每k个一组翻转#

每k个节点翻转一组的python实现

# class ListNode:
#     def __init__(self, x):
#         self.val = x
#         self.next = None
#
# 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
#
# 
# @param head ListNode类 
# @param k int整型 
# @return ListNode类
#
class Solution:
    def reverseKGroup(self , head: ListNode, k: int) -> ListNode:
        # write code here
        dummy = ListNode(0)
        dummy.next = head
        pre, end = dummy, dummy
        while end.next:
            for i in range(k):
                if end:
                    end = end.next
            if not end: break
            #把子表孤立出来
            start = pre.next
            start_next = end.next
            end.next = None
            #完成子表的反转
            pre.next = self.reverseList(start)
            start.next = start_next
            pre = start
            end = start
        return dummy.next
    
    def reverseList(self, head):
        pre = None
        cur = head
        while cur:
            cur.next, cur, pre = pre, cur.next, cur
        return pre