Remove Nth node from the end of a Linked List.cpp

class Solution {
public:
    ListNode* removeNthFromEnd(ListNode* head, int n) {
        ListNode * start = new ListNode();
        start -> next = head;
        ListNode* fast = start;
        ListNode* slow = start;     

        for(int i = 1; i <= n; ++i)
            fast = fast->next;
    
        while(fast->next != NULL)
        {
            fast = fast->next;
            slow = slow->next;
        }
        
        slow->next = slow->next->next;
        
        return start->next;
    }
};