leetcode(面试题 02.02. 返回倒数第 k 个节点)

一.蠢办法（使用循环进行查找）

var kthToLast = function(head, k) {var dummy = new ListNode(0);dummy = head;var length = 0;while(dummy!=null){length++;dummy = dummy.next;}console.log("长度为:"+length);var buchang = 0;var didian = length - k;while(buchang != didian){buchang++;head = head.next;}return head.val;
};

二.使用快慢指针

var kthToLast = function(head, k) {var fast = new ListNode(0);var slow = new ListNode(0);fast = head;slow = head;while(k!=0){fast = fast.next;k--;}while(fast!=null){fast=fast.next;slow = slow.next;}return slow.val;
};