题解 | #链表中倒数最后k个结点#

思路
经典双指针题目，leftPoint指向第一个节点，rightPoint指向第k个节点，左右指针相距k-1个身位，使用rightPoint去寻找尾节点，当寻找到尾节点时，那么leftPoint指向的节点便是倒数第k个节点了。

结果
运行时间：16ms
占用内存：10828KB

代码

 public ListNode FindKthToTail (ListNode pHead, int k) {
        ListNode leftPoint = pHead;
        ListNode rightPoint = pHead;
        if (k <= 0) return null;
        for (int i = 0; i < k - 1; i++) {
            if (rightPoint == null ||
                    rightPoint.next == null){
                return null;
            }
            rightPoint = rightPoint.next;
        }

        while (rightPoint.next != null){
            rightPoint = rightPoint.next;
            leftPoint = leftPoint.next;
        }


        return leftPoint;
    }