A character in UTF8 can be from 1 to 4 bytes long, subjected to the following rules: For 1-byte character, the first bit is a 0, followed by its unicode code. For n-bytes character, the first n-bits are all one's, the n+1 bit is 0, followed by n-1 by…

wand(weak and)算法基本思路 一般搜索的query比较短,但如果query比较长,如是一段文本,需要搜索相似的文本,这时候一般就需要wand算法,该算法在广告系统中有比较成熟的应 该,主要是adsense场景,需要搜索一个页面内容的相似广告. Wand方法简单来说,一般我们在计算文本相关性的时候,会通过倒排索引的方式进行查询,通过倒排索引已经要比全量遍历节约大量时间,但是有时候仍 然很慢. 原因是很多时候我们其实只是想要top n个结果,一些结果明显较差的也进行了复杂的相关性计算,而…

946. Validate Stack Sequences 题目描述 Given two sequences pushed and popped with distinct values, return true if and only if this could have been the result of a sequence of push and pop operations on an initially empty stack. 示例 示例1 Input: pushed = [1,…

A character in UTF8 can be from 1 to 4 bytes long, subjected to the following rules: For 1-byte character, the first bit is a 0, followed by its unicode code. For n-bytes character, the first n-bits are all one's, the n+1 bit is 0, followed by n-1 by…

详见:https://leetcode.com/problems/utf-8-validation/description/ C++: class Solution { public: bool validUtf8(vector<int>& data) { int cnt = 0; for (int d : data) { if (cnt == 0) { if ((d >> 5) == 0b110) { cnt = 1; } else if ((d >> 4)…

转(http://www.codeceo.com/article/java-string-ansi-unicode-bmp-utf.html#0-tsina-1-10971-397232819ff9a47a7b7e80a40613cfe1) 概念总结 早期,互联网还没有发展起来,计算机仅用于处理一些本地的资料,所以很多国家和地区针对本土的语言设计了编码方案,这种与区域相关的编码统称为ANSI编码(因为都是对ANSI-ASCII码的扩展).但是他们没有事先商量好怎么相互兼容,而是自己搞自己的,这样…

Given n nodes labeled from 0 to n - 1 and a list of undirected edges (each edge is a pair of nodes), write a function to check whether these edges make up a valid tree. For example: Given n = 5 and edges = [[0, 1], [0, 2], [0, 3], [1, 4]], return tru…

Given a binary tree, determine if it is a valid binary search tree (BST). Assume a BST is defined as follows: The left subtree of a node contains only nodes with keys less than the node's key. The right subtree of a node contains only nodes with keys…

<?php /** * 常用的正则表达式来验证信息.如:网址 邮箱 手机号等 */ class check { /** * 正则表达式验证email格式 * * @param string $str    所要验证的邮箱地址 * @return boolean */ public static function isEmail($str) { if (!$str) { return false; } return preg_match('#[a-z0-9&\-_.]+@[\w\-_]+([\…

Given a string containing only three types of characters: '(', ')' and '*', write a function to check whether this string is valid. We define the validity of a string by these rules: Any left parenthesis '(' must have a corresponding right parenthesi…