删除单链表中倒数第k个结点（简化）c语言

/**
* Definition for singly-linked list.
* struct ListNode {
* int val;
* struct ListNode *next;
* };
*/
struct ListNode* removeNthFromEnd(struct ListNode* head, int n) {
struct ListNode *fast = head, *slow = head;
// fast指针先走n步
for (int i = 0; i < n; i++) {
fast = fast->next;
}
// 如果fast指针已经到了链表尾部，说明要删除的是头结点
if (fast == NULL) {
head = head->next;
free(slow);
return head;
}
// 同时移动fast和slow指针，直到fast到达链表尾部
while (fast->next != NULL) {
fast = fast->next;
slow = slow->next;
}
// 删除倒数第n个结点
struct ListNode* tmp = slow->next;
slow->next = slow->next->next;
free(tmp);
return head;
}