面试题22. 链表中倒数第k个节点

[fireairforce]

直接模拟就可以啦:

/**
 * Definition for singly-linked list.
 * function ListNode(val) {
 *     this.val = val;
 *     this.next = null;
 * }
 */
/**
 * @param {ListNode} head
 * @param {number} k
 * @return {ListNode}
 */
var getKthFromEnd = function(head, k) {
   let len = 0;
   let lenHead = head;
   while(lenHead) {
       lenHead = lenHead.next;
       len ++;
   }
   k = k % len;
   if(k === 0) {
       return head;
   }
   let preHead = head;
   let realHead = head;
   for(let i = 0;i<k;i++) {
       preHead = preHead.next;
   }
   while(preHead) {
       realHead = realHead.next;
       preHead = preHead.next;
   }
   return realHead;
};