BM9 删除链表的倒数第n个节点

删除倒数第 n 个节点。

双指针。

class Solution {
public:
    
    ListNode* removeNthFromEnd(ListNode* head, int n) {
        // write code here
        ListNode* tt = new ListNode(-1);
        tt->next = head;
        ListNode* slow = tt;
        ListNode* fast = tt;
        while(slow && fast)
        {
            for(int i = 0; i <= n; i++)
            {
                fast = fast->next;
            }
            if(fast == NULL)
            {
                slow->next = slow->next->next;
                break;
            }
            slow = slow->next;
            fast = slow;
        }
        return tt->next;
    }
};