题解 | #链表中的节点每k个一组翻转#

package main

import . "nc_tools"

/*
 * type ListNode struct{
 *   Val int
 *   Next *ListNode
 * }
 */

/**
 *
 * @param head ListNode类
 * @param k int整型
 * @return ListNode类
 */
func reverseKGroup(head *ListNode, k int) *ListNode {
	// write code here
	if head == nil || head.Next == nil || k == 1 {
		return head
	}
	node := new(ListNode)
	node.Next = head
	total := 0
	ptr := node
	for ptr.Next != nil {
		ptr = ptr.Next
		total++
	}
	count := total / k
	pre := node
	for i := 0; i < count; i++ {
		pHead := pre.Next
		for j := 0; j < k-1; j++ {
			cur := pHead.Next
			pHead.Next = cur.Next
			cur.Next = pre.Next
			pre.Next = cur
		}
		pre = pHead
	}
	return node.Next
}