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 ) {
    // write code here
    if (head == NULL)
        return NULL;
    struct ListNode* dummy = (struct ListNode*)malloc(sizeof(struct ListNode));
    dummy->next = head;
    head = dummy;
    struct ListNode* front = head;
    struct ListNode* rear = head;
    for (int i = 0; i < n; i++)
        front = front->next;
    while (front->next != NULL) {
        front = front->next;
        rear = rear->next;
    }
    struct ListNode* tmp = rear->next;
    rear->next = rear->next->next;
    free(tmp);
    return dummy->next;
}