题目描述

在这里插入图片描述

题解

求得链表长度，得出正向遍历的次数，使用快慢指针，删除对应结点

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class Solution {
public:
    int getlen(ListNode* head)
    {
        int count = 0;
        while(head != NULL)
        {
            ++count;
            head = head->next;
        }
        return count;
    }
    ListNode* removeNthFromEnd(ListNode* head, int n) {
        if(n <= 0) return nullptr;
        ListNode* fast = head;
        ListNode* slow = NULL;
        int forward = getlen(head) - n;
        if(forward == 0) return head->next;
        while(forward--)
        {
            slow = fast;
            fast = fast->next;
        }
        slow->next = fast->next;
        return head;
    }
};