BM8 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

        if (pHead == null || k == 0) {
            return null;
        }

        Stack<ListNode> stack = new Stack();

        while (pHead != null) {
            stack.push(pHead);
            pHead = pHead.next;
        }

        ListNode node = null;

        while (!stack.isEmpty()) {
            node = stack.pop();
            if (--k == 0) {
                return node;
            }
        }
        return null;
    }
}