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
        if(head==nullptr || n<1) return nullptr;

        ListNode newHead(0);
        newHead.next=head;

        ListNode *l1=head;
        ListNode *l2=head;

        for(int i=0;i<n;i++){
            l2=l2->next;
        }

        ListNode *p=&newHead;
        while(l2){
            p=l1;
            l2=l2->next;
            l1=l1->next;
        }

        p->next=l1->next;
        delete l1;

        return newHead.next;

    }
};