Return the Later Middle Node of a Singly Linked List
Company: Google
Role: Software Engineer
Category: Coding & Algorithms
Difficulty: easy
Interview Round: Other
### Problem
Return the middle node pointer of the singly linked list beginning at `head`. If the list has two middle nodes, return the second one. Example output lists show the suffix beginning at the returned existing node; the function does not return a new array or copied list.
```cpp
class Solution {
public:
ListNode* middleNode(ListNode* head);
};
```
### Examples
**Example 1:**
```text
Input: head = [8,2,9]
Output: node with value2, suffix[2,9]
Explanation: The middle is the second node, whose value is2.
```
**Example 2:**
```text
Input: head = [6,1,4,7]
Output: node with value4, suffix[4,7]
Explanation: The two middle positions are2 and3; choose position3.
```
### Constraints
- The list contains1 to100 nodes.
- `1 <= Node.val <= 100`.
### Contract considerations
The list is nonempty, so the returned pointer exists. The native ListNode interface and supplied type definition remain unchanged.
```hint Read the boundary condition
Compare where a two-step pointer stops for odd and even list lengths.
```
### Boundary reminders
The list is nonempty, so the returned pointer exists. The native ListNode interface and supplied type definition remain unchanged.
Overview: Return the Later Middle Node of a Singly Linked List. Return the middle node pointer of the singly linked list beginning at head.