链表中倒数第k个结点

public class ListNode {
    int val;
    ListNode next = null;

    ListNode(int val) {
        this.val = val;
    }
}*/
public class  {
    public ListNode FindKthToTail(ListNode head,int k) {
        int total=0;
        if(head==null)
            return null; //这里的参数非null判断其实不加也行，若head为null则下面的代码也会返回null

        ListNode node=head;
        while(node!=null){
            total++;
            node=node.next;
        }
        if(k<=total){
            node=head;
            for(int i=1; i<=total-k; i++){
                node=node.next;
            }
            return node;
        }
        return null;
    }
}