题解 | #删除链表的倒数第n个节点#

/**
 * struct ListNode {
 *    int val;
 *    struct ListNode *next;
 * };
 *
 * C语言声明定义全局变量请加上static，防止重复定义
 */
/**
 * 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 ) {
    int s = 0;
    struct ListNode* L = head;
    while (L != NULL)
    {
        s++;
        L = L->next;
    }
    struct ListNode* pre = head;
    int k = s - n;
    if (k == 0)
    {
        return pre->next;
    }
    for (int i = 0; i < k - 1; i++)
    {
        pre = pre->next;
    }
    pre->next = pre->next->next;
    return head;
}