题解 | #链表中倒数最后k个结点#

// 为什么的我python不能用
    // def FindKthToTail(self, pHead, k):
    //     phead = pHead
    //     len = 0
    //     a = 0
    //     while phead != None:
    //         phead = phead.next
    //         len = len + 1
    //     a = len - k
    //     if a > 0:
    //         while a != 0:
    //             pHead = pHead.next
    //             a = a-1
    //         return pHead
    //     if a == 0:
    //         return pHead
    //     if a < 0:
    //         return None
import java.util.*;

/*
 * public class ListNode {
 *   int val;
 *   ListNode next = null;
 *   public ListNode(int val) {
 *     this.val = val;
 *   }
 * }
 */

public class Solution {
    /**
     * 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
     */
    public ListNode FindKthToTail (ListNode pHead, int k) {
        // write code here
        ListNode first = pHead;
        for(int  i= 0;i<k;i++){
            if(first == null) return first;
            first = first.next;

        }
        ListNode last = pHead;
        while(first!=null){
            first = first.next;
            last = last.next;
        }
        return last;
    }
}