《剑指Offer》题目：链表中倒数第k个结点

class ListNode {
    int val;
    ListNode next = null;
    ListNode(int val) {
        this.val = val;
    }
}
public class FindKthToTail {
    public ListNode FindKthToTail(ListNode head,int k) {
        ListNode listNode = head;
        if (listNode == null) return null;
        int temp = 0;
        while (listNode != null){
            listNode = listNode.next;
            temp++;
        }
        if(k>temp) return null;
        temp = temp - k + 1;
        ListNode listNode1 = head;
        while (temp > 1){
            listNode1 = listNode1.next;
            temp--;
        }
        return listNode1;
    }
}