Remove Linked List Elements

Given the head of a linked list and an integer key, remove all the nodes of the linked list that has Node.data == key, and return the new head.

Class Node:
    data (int)
    next (Node)

Input Format

First Parameter - Node head

Second Parameter - number key

Output Format

Return the node.

Example 1:

Input:  1 2 6 7 5 7
        7
Output:  1 2 6 5

Explanation:
Here we want to delete node having value 7 , and return the List . 

Example 2:

Input: 5 5 5 5 5
       5
Output: (NULL)

Constraints:

• The number of nodes in the list is in the range [0, 10⁴].
• 1 <= Node.data <= 10⁴
• 0 <= key <= 10⁴
• Expected Time Complexity: O(N)
• Expected Space Complexity: O(1)