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
    int count = -n;
    struct ListNode* nh1 = head;
    struct ListNode* nh2 = head;
    while(nh1 != NULL){
        count++;
        nh1 = nh1->next;
    }
    if(count < 0){
        return head;
    }else if(count == 0){
        return head->next;
    }
    while(nh2 != NULL){
        count--;
        if(count <= 0 && nh2->next != NULL){
           nh2->next = nh2->next->next; 
           break;
        }
        nh2 = nh2->next;
    }
    return head;
}