Provide an interface for creating families of related or dependent objects without specifying their concrete classes.（为创建一组相关或相互依赖的对象提供一个接口，而且无须指定它们的具体类。）《设计模式之禅》

Suppose an array sorted in ascending order is rotated at some pivot unknown to you beforehand.(i.e., 0 1 2 4 5 6 7 might become 4 5 6 7 0 1 2).You are given a target value to search. If found in the array return its index, otherwise return -1.题目的输入是一个被旋转过的升序排列数组。（如正常的升序...

Given a binary tree, determine if it is a valid binary search tree (BST).

Given a non-empty binary search tree and a target value, find the value in the BST that is closest to the target.

Given a 2D board and a list of words from the dictionary, find allwords in the board.Each word must be constructed from letters of sequentially adjacentcell, where "adjacent" cells are those horizontally or verticallyneighboring. The same letter cell may not be used more than once in aword.Exampl...

Given n, how many structurally unique BST's (binary search trees) that store values 1 ... n?

Suppose an array sorted in ascending order is rotated at some pivot unknown to you beforehand.(i.e.,[0,1,2,4,5,6,7]might become[4,5,6,7,0,1,2]). You are given a target value to search. If found in the array return its index, otherwise return-1. You may assume no duplicate exists in the array. You...

作用：二分查找适用于有序的的数组或列表中，如果列表及数组中有n个元素，通过二分查找查询某一元素的位置需要的步骤是log(n)（注：该log的底数是2）；

[链接] ie8 支持position:fixed

国内的有个不错的 xun-search;

[链接]

cad-engine 这个包在 npm 上没了。把这个依赖先去掉再安装下

{代码...}

数据区：map结构，shardId-->Shard结构，一个shard可以理解为单独的tsm引擎，其中包含wal、tsm file等数据；

说明配置确实被正确初始化了，问题是只有刷新页面进行服务端渲染时才有这个日志，这时的path是页面路由而不是api请求，而页面上的请求却没有被代理。很奇怪，不知道是哪里配置有问题，请各路大神帮忙。

elasticsearch-6.2.2启动后CURL请求后报 master_not_discovered_exception错误环境说明：192.168.33.10 master 192.168.33.11 master data 192.168.33.12 master data

这个方法的意思就是给一下标$key取出对应val的值，我在方法最后return $v，然后我把这个return的结果赋给一个值$va，这个值始终为空，但是我在方法最后打印$v的时候是有值的，为什么会这样呢？是变量作用域的问题还是我代码写的不规范导致的？求解