题解 | #删除链表的倒数第n个节点#

1.双指针遍历法

/**
 * 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) {
            return head;
        }
        ListNode* fast = head;
        for(int i=0;i<n;i++) {
            fast = fast->next;
        }
        if(fast==nullptr) {
            return head->next;
        }
        ListNode* slow = head;
        while(fast->next) {
            fast = fast->next;
            slow = slow->next;
        }
        slow->next = slow->next->next;
        return head;
    }
};