Kth Node From Middle

Given a linked list A of length N and an integer B.

You need to find the value of the B^th node from the middle towards the beginning of the Linked List A.

If no such element exists, then return -1.

NOTE:

• Position of middle node is: (N/2)+1, where N is the total number of nodes in the list.

• 1 <= N <= 10⁵
• 1<= Value in Each Link List Node <= 10³
• 1 <= B <= 10⁵

First argument is the head pointer of the linkedlist A.

Second argument is an integer B.

Return an integer denoting the value of the B^th from the middle towards the head of the linked list A. If no such element exists, then return -1.

Input 1:

 A = 3 -> 4 -> 7 -> 5 -> 6 -> 1 6 -> 15 -> 61 -> 16
 B = 3

Input 2:

 A = 1 -> 14 -> 6 -> 16 -> 4 -> 10
 B = 2

Input 3:

 A = 1 -> 14 -> 6 -> 16 -> 4 -> 10
 B = 10

Output 1:

 4

Output 2:

 14

Output 3:

 -1

Explanation 1:

 The Middle of the linked list is the node with value 6.
 The 1st node from the middle of the linked list is the node with value 5.
 The 2nd node from the middle of the linked list is the node with value 7.
 The 3rd node from the middle of the linked list is the node with value 4.
 So we will output 4.

Explanation 2:

 The Middle of the linked list is the node with value 16.
 The 1st node from the middle of the linked list is the node with value 6.
 The 2nd node from the middle of the linked list is the node with value 14.
 So we will output 14.

Explanation 3:

 The Middle of the linked list is the node with value 16.
 There are only 3 nodes to the left of the middle node and we need to find the 10th node which doesn't exist so we will return -1.