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
 *
 * 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 ) {
    // write code here
    struct ListNode* p0;
    p0 = head;
    int k=0;
    int i=0;
    struct ListNode* pre;
    struct ListNode* cur;
    struct ListNode* nex;
    pre = NULL;
    cur = head;
    nex = NULL;
    while(p0!=NULL)
    {
        k++;
        p0 = p0->next;
    }
    if(n==k)
    {
        head = head->next;
    }
    else
    {
        while(i<(k-n))
        {
            nex = cur->next;
            pre = cur;
            cur = nex;
            i++;
        }
        nex = cur->next;
        pre->next = nex;
        cur->next = NULL;
    }
    
    
    return head;
}