题解 | #链表中倒数最后k个结点#

/**
 * 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 pHead ListNode类 
 * @param k int整型 
 * @return ListNode类
 */
struct ListNode* FindKthToTail(struct ListNode* pHead, int k ) {
    // write code here
    struct ListNode *slow = pHead;
    struct ListNode *fast = pHead;

    if (pHead == NULL) {
        return pHead;
    }

    for (int i = 0; i < k; i++) {
        if (fast == NULL) {
            return NULL;
        }
        fast = fast->next;
    }

    while (fast) {
        slow = slow->next;
        fast = fast->next;
    }

    return slow;
}