> For the complete documentation index, see [llms.txt](https://mayanktyagi3111.gitbook.io/interview-prep/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://mayanktyagi3111.gitbook.io/interview-prep/linked-list/reverse-linked-list-ii.md).

# Reverse Linked List II

Reverse a linked list from position *m* to *n*. Do it in one-pass.

**Note:** 1 ≤ *m* ≤ *n* ≤ length of list.

**Example:**

```
Input: 1->2->3->4->5->NULL, m = 2, n = 4
Output: 1->4->3->2->5->NULL
```

```java
class Solution {
    public ListNode reverseBetween(ListNode head, int m, int n) {
        if (head == null)
            return head;
        int index = 1;
        ListNode temp = head, previous = null, start = null, end = null;
        while (temp != null) {
            if (index + 1 == m)
                previous = temp;
            else if (index == m) {
                start = temp;
                ListNode prev = null;
                while (index <= n) {
                    if (index == n)
                        end = temp;
                    ListNode t = temp.next;
                    temp.next = prev;
                    prev = temp;
                    temp = t;
                    index++;
                }
                if (previous != null)
                    previous.next = end;
                else 
                    head = end;
                start.next = temp;
                break;
            }
            temp = temp.next;
            index++;
        }
        return head;
    }
}
```