题解 | #链表中的节点每k个一组翻转#

import . "nc_tools"

func reverseKGroup( head *ListNode ,  k int ) *ListNode {
    h := &ListNode{Next: head}
    ret, tail := h, head
    
    for i := 1;tail != nil;i++ {
        tail = tail.Next
        if i == k {
            if h, i= reverse(h, tail), 0;h != nil {
                tail = h.Next
            }
        }
    }
    return ret.Next
}

func reverse(head, tail * ListNode) *ListNode { // head -> 之间的节点翻转 <-tail
    if head == nil {
        return nil
    }
    p := head.Next
    for ;p != nil && p.Next != nil && p.Next != tail ; {
        s := p.Next
        p.Next = s.Next
        s.Next = head.Next
        head.Next = s
    }
    return p
}