19. Remove Nth Node From End of List

/**
 * 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 *h=head,*l=head;
        for(int i=0;i<n;i++){
            if(h->next==NULL){
                if(i==n-1)
                    head=head->next;
                return head;
            } 
            h=h->next;
        }
        while(h->next!=NULL){
            l=l->next;
            h=h->next;
        }
        l->next=l->next->next;
        return head;
    }
};