19. Remove Nth Node From End of List.cpp

/**
 * Definition for singly-linked list.
 * struct ListNode {
 *     int val;
 *     ListNode *next;
 *     ListNode() : val(0), next(nullptr) {}
 *     ListNode(int x) : val(x), next(nullptr) {}
 *     ListNode(int x, ListNode *next) : val(x), next(next) {}
 * };
 */
class Solution {
public:
    ListNode* removeNthFromEnd(ListNode* head, int n) {
        ListNode* temp = new ListNode(0,head);
        ListNode* left = temp;
        ListNode* right = head;
        
        for(int i=0; i < n; i++) right = right -> next;
        
        while(right != nullptr){
            right = right -> next;
            left = left -> next;
        }
        ListNode* node_to_remove = left -> next;
        left -> next = left -> next -> next;
        
        delete node_to_remove;
        
        return temp->next;
    }
};