RemoveNthNode_BF.cpp

/**
 * Definition for singly-linked list.
 * struct ListNode {
 *     int val;
 *     ListNode *next;
 *     ListNode(int x) : val(x), next(NULL) {}
 * };
 */
class Solution {
public:
    ListNode* removeNthFromEnd(ListNode* head, int n) {
        int len = 0;
        ListNode* h = head;
        while(head){
            len++;
            head = head->next;
        }
        if(len == 1){
            return h->next;
        }
        head = h;
        int index = len - n;
        if(index == 0) return head->next;
        
        for(int i = 0; i< index - 1; i++){
            head = head->next;
        }
        ListNode *temp = head->next;
        head->next = head->next->next;
        delete temp;
        return h;
        
    }
};