题解 | #删除链表的倒数第n个节点#

 * struct ListNode {
 *	int val;
 *	struct ListNode *next;
 * };
 */

class Solution {
public:
    /**
     * 
     * @param head ListNode类 
     * @param n int整型 
     * @return ListNode类
     */
    ListNode* removeNthFromEnd(ListNode* head, int n) {
        // write code here
        ListNode *r,*l;
        r=l=head;
        int m=0,k=0;
        while(r){
            ++m;
            if(m<=n+1){
                k=n+1-m;
                r=r->next;
            }
            else {
                r=r->next;
                l=l->next;
            }
        }
        if(k==1){
            head=head->next;
        }
        else {
            r=l->next;
            l->next=r->next;
        }
        return head;
    }
};