题解 | #删除链表的倒数第n个节点#

/**
 * struct ListNode {
 *	int val;
 *	struct ListNode *next;
 *	ListNode(int x) : val(x), next(nullptr) {}
 * };
 */
class Solution {
public:
    /**
     * 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
     *
     * 
     * @param head ListNode类 
     * @param n int整型 
     * @return ListNode类
     */
    ListNode* removeNthFromEnd(ListNode* head, int n) {
        
        ListNode LL = ListNode(-1);
        ListNode* PreHead = ≪
        PreHead->next = head;

        ListNode* pre = PreHead, *fast = PreHead, *temp = nullptr;
        for(int i=0; i < n; i++){
            if(!fast) return head;
            fast = fast->next;
        }
        while (fast->next) {
            fast = fast->next;
            pre = pre->next;
        }

        temp = pre->next->next;
        delete pre->next;
        pre->next = temp;

        return PreHead->next;

    }
};