题解 | 链表中倒数最后k个结点

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
        int n = 0;
        ListNode one = pHead;
        while(one != null) {
            one = one.next;
            n++;
        }
        System.out.println(n);

        if(n < k) return null;

        ListNode head = pHead;
        for(int i = 1; i <= n - k; i++)  {
            head = head.next;
        }

        return head;
    }
}