Write a function named insert that accepts a reference to a pointer to a ListNode representing the front of a linked list, along with an index and an integer value.
Your function should insert the given value into a new node at the end of the list.
For example, suppose a variable named front points to the front of a list containing the following sequence of values:
{8, 23, 19, 7, 102}
The call of insert(front, 2, 42); should insert the value 42 at index 2, changing the list to store the following:
{8, 23, 42, 19, 7, 102}
The other values in the list should retain the same order as in the original list.
You may assume that the index passed is between 0 and the existing size of the list, inclusive.
Constraints:
Do not modify the data field of existing nodes; change the list by changing pointers only.
Do not use any auxiliary data structures to solve this problem (no array, vector, stack, queue, string, etc).
Assume that you are using the ListNode structure as defined below:
struct ListNode {
int data; // value stored in each node
ListNode* next; // pointer to next node in list (nullptr if none)
}
