ethan w.-优快云博客

转载二维码QRCODE原理详解

QR(Quick-Response) CODE是被广泛使用的一种二维码，解码速度快。如上图是一个二维码的基本结构，其中：位置探测图形、位置探测图形分隔符、定位图形：用于对二维码的定位，对每个QR码来说，位置都是固定存在的，只是大小规格会有所差异;校正图形：规格确定，校正图形的数量和位置也就确定了;格式信息：表示该二维码的纠错级别，分为L、M、Q、H;版本信息：即二维码的规格，Q...

2019-04-25 18:30:32 6212

原创 Sharding-JDBC分布式ID生成算法snowflake源码详细解读

分布式ID生成算法的有很多种，Twitter的SnowFlake就是其中经典的一种。Snowflake工作原理对于分布式的ID生成，以Twitter Snowflake为代表的Flake 系列算法，属于划分命名空间并行生成的一种算法，生成的数据为64bit的long型数据，在数据库中应该用大于等于64bit的数字类型的字段来保存该值，比如在MySQL中应该使用BIGINT。SnowFl...

2019-04-24 23:32:34 7046 1

find the sum of the even-valued terms

Each new term in the Fibonacci sequence is generated by adding the previous two terms. By starting with 1 and 2, the first 10 terms will be:1, 2, 3, 5, 8, 13, 21, 34, 55, 89, ...By considering...

2011-02-27 18:58:10 309

原创 Swallows may have gone——也许燕子已经飞去

[b][size=medium]Swallows may have gone——也许燕子已经飞去Swallows may have gone, but there is a time of return; willow trees mayhave died back, but there is a time of regreening; peach blossoms mayhave fal...

2009-09-18 11:37:26 450

原创 Youth

[b][size=medium][align=center]Youth---by Samuel Erman[/align] Youth is not a time of life, it is a state of mind, it is not a matter of rosy cheeks, red lips, supple knees. It is a matter of the...

2009-09-18 11:29:14 129

Find the sum of all the multiples of 3 or 5 below

If we list all the natural numbers below 10 that are multiples of 3 or 5, we get 3, 5, 6 and 9. The sum of these multiples is 23.Find the sum of all the multiples of 3 or 5 below 1000.[code="j...

2009-02-19 10:22:12 370