0092. Reverse Linked List I I | LeetCode Cookbook

[halfrost]

https://books.halfrost.com/leetcode/ChapterFour/0001~0099/0092.Reverse-Linked-List-II/

[hehelv]

/**

• Definition for singly-linked list.

• type ListNode struct {

• Val int
  

• Next *ListNode
  

• } */ func reverseBetween(head *ListNode, left int, right int) *ListNode { dummyHead := &ListNode{Next: head} pre := dummyHead

  for i := 1; i < left; i++ { pre = pre.Next }

  last := pre.Next for i := left; i <= right; i++ { last = last.Next }

  pre.Next = reverse(pre.Next, last) if dummyHead.Next == head { return head } return pre.Next }

func reverse(first *ListNode, last *ListNode) *ListNode { pre, p := first, first.Next

pre.Next = last
for p != last {
    tmp := pre
    pre = p
    p = p.Next
    pre.Next = tmp
}

return pre

}