Reverse an Inclusive Segment of List Nodes
Company: Bloomberg
Role: Software Engineer
Category: Coding & Algorithms
Difficulty: medium
Interview Round: Other
### Problem
Reverse the nodes from position `left` through position `right` in a singly linked list, leaving the rest in its original order. Positions are one-based and inclusive. Return the resulting head using the supplied `ListNode` type with `val` and `next` fields.
```cpp
ListNode* reverseBetween(ListNode* head, int left, int right);
```
### Examples
```text
Input: head = [8,1,6,3,9], left = 2, right = 5
Output list: [8,9,3,6,1]
```
```text
Input: head = [4,7,2], left = 1, right = 2
Output list: [7,4,2]
```
Brackets show the list's values; both the input and result remain node pointers.
### Constraints
- The list has `n` nodes, with `1 <= n <= 500`.
- Node values are between -500 and 500, inclusive.
- `1 <= left <= right <= n`.
### Source follow-up
Can the reversal be done in one pass?
Overview: Reverse an inclusive one-based linked-list segment through pointer changes, including a one-pass follow-up.