剑指offer【13】- 链表中倒数第k个结点

输入一个链表，输出该链表中倒数第k个结点。

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

    ListNode(int val) {
        this.val = val;
    }
}*/
public class Solution {
    public ListNode FindKthToTail(ListNode head,int k) {
        
        if(head == null){
            return head;
        }
        int count = 0;
        ListNode list = head;
        
        while(list != null){
            count++;
            list = list.next;
        }
        if(k > count){
            return null;
        }
        
        ListNode node = head;
        for(int i = 0; i < count -k; i++){
            node = node.next;
        }
        return node;

    }
}