# [Solved] Given the head of a singly linked list and two integers left and right where left <= right, reverse the nodes of the list from position left to position right, and return the reversed list.

## Question

Given the `head` of a singly linked list and two integers `left` and `right` where `left <= right`, reverse the nodes of the list from position `left` to position `right`, and return the reversed list.

Example 1:

```Input: head = [1,2,3,4,5], left = 2, right = 4
Output: [1,4,3,2,5]
```

Example 2:

```Input: head = [5], left = 1, right = 1
Output: [5]
```

Constraints:

• The number of nodes in the list is `n`.
• `1 <= n <= 500`
• `-500 <= Node.val <= 500`
• `1 <= left <= right <= n`

Follow up: Could you do it in one pass?

## Python Solution

```# Definition for singly-linked list.
# class ListNode:
#     def __init__(self, val=0, next=None):
#         self.val = val
#         self.next = next
class Solution:
def reverseBetween(self, head: ListNode, left: int, right: int) -> ListNode:
dummy = ListNode(0)

leftportion = dummy

for _ in range(left-1):
leftportion = leftportion.next

curr = leftportion.next
x = curr
prev = None

for _ in range(right-left+1):
nex = curr.next
curr.next = prev
prev,curr = curr,nex

leftportion.next = prev
x.next = nex
return dummy.next```