输出单向链表中倒数第k个结点

import java.util.Scanner;
class ListNode {
int val;
ListNode next = null;

ListNode(int val) {
    this.val = val;
}

}
public class 快乐数{
public ListNode FindKthToTail(ListNode head,int k) {
if(head==null){
return null;
}
int count=1;
ListNode cur=head;
while(head.next!=null){
head=head.next;
count++;
}
if(k>count){
return null;
}
for(int i=0;i<count-k;i++){
cur=cur.next;
}
return cur;
}

}