题解 | #删除链表的倒数第n个节点#

/**
 * struct ListNode {
 *	int val;
 *	struct ListNode *next;
 * };
 */
/**
 * 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
 */
struct ListNode* removeNthFromEnd(struct ListNode* head, int n ) {
    if(head == NULL || n == 0)
    {
        return NULL;
    }
    struct ListNode *pHead = (struct ListNode *)malloc(sizeof(struct ListNode));
    pHead->next = head;
    struct ListNode *fast = pHead;
    struct ListNode *slow = pHead;
    for(int i = 0;i < n;i++)
    {
        fast = fast->next;
    }
    while (fast->next != NULL) 
    {
        fast = fast->next;
        slow = slow->next;
    }   

    struct ListNode *p = (struct ListNode *)malloc(sizeof(struct ListNode));
    p= slow->next;
    slow->next = slow->next->next;

    free(p);
    p = NULL;

    struct ListNode *result = pHead->next;
    free(pHead);
    
    return result;
}