Given the head of a Singly Linked List and an index, The task is to find the node at the given index(1-based index) of the linked list. If no such index exists then return -1.
Examples :
Input: LinkedList: 1->2->3->4->5->6->7 , index = 3
Output: 3
Explanation: The Node value at index 3 is 3.
Input: LinkedList: 19->28->37->46->55 , index = 6
Output: -1
Explanation: As number of nodes are less than k so there is no node at index 6 , therefore our answer is -1.
Expected Time Complexity: O(n)
Expected Auxiliary Space: O(1)
Constraints:
1 <= number of nodes <= 105
1 <= node->data , k <= 105