Du Yao's blog

2015-10-27

2.4

最大的leftMax与rightMax之差的绝对值给定一个长度为N(N>1)的整型数组arr，可以划分成左右两个部分，左部分arr[0..K]，右部分arr[K+1..N-1]，K可以取值的范围是[1,N-2]。求这么多划分方案中，左部分中的最大值减去右部分最大值的绝对值，最大是多少？例如[2,7,3,1,1]，当左部分为[2,7]，右部分为[3,1,1]时，左部分中的最大值减去右部分最大值的绝对值为4。当左部分为[2,7,3]，右部分为[1,1]时，左部分中的最大值减去右部分最大值的绝对值为6。还有很多划分方案，但最终返回6。阅读全文...

2015-10-26

2.3

题目给定一个无序数组arr，求出需要排序的最短子数组长度。例如：arr = [1，5，3，4，2，6，7]返回4，因为只有[5，3，4，2]需要排序。阅读全文...

2015-10-25

2.2

从5随机到7随机及其扩展基本题目题目给定一个等概率随机产生1~5的随机函数rand1To5如下：public int rand1To5() {return (int) (Math.random() * 5) + 1;}除此之外不能使用任何额外的随机机制，请用rand1To5实现等概率随机产生1~7的随机函数rand1To7。阅读全文...

2015-10-25

1.2

题目：给定一个字符串str和str的最长回文子序列strLPS，返回字符串str在任意位置添加最少字符后，整体都是回文串的其中一种结果。例如：str = “B1G2TY34I3OPX2S1”;strLPS = “123I321”;返回：B1GS2TYXPO34I43OPXYT2SG1B注意：也可以返回B1SG2XPOTY34I43YTOPX2GS1B，总之返回一种满足条件的结果即可。阅读全文...

2015-10-25

1.1

实现“之”字形打印矩阵输入一个矩阵，按照从之字形打印出每一个数字，例如，如果输入如下矩阵：1 2 3 45 6 7 89 10 11 1213 14 15 16则依次打印出数字1 5 2 3 6 9 13 10 7 4 8 11 14 15 12 16 阅读全文...

2015-10-24

Programmatic Transaction

IntroductionProgrammatic transaction management approach allows you to manage the transaction with the help of programming in your source code. That gives you extreme flexibility, but it is difficult to maintain. SEE MORE: Programmatic Transaction 阅读全文...

2015-10-24

Declarative Transaction

IntroductionDeclarative transaction management approach allows you to manage the transaction with the help of configuration instead of hard coding in your source code. This means that you can separate transaction management from the business code. You only use annotations or XML based configuration to manage the transactions. The bean configuration will specify the methods to be transactional. SEE MORE:Declarative Transaction 阅读全文...

2015-10-24

Isolation

IsolationIntroductionIsolation is typically defined at database level as a property that defines how/when the changes made by one operation become visible to other. Isolation is one of the ACID (Atomicity, Consistency, Isolation, Durability) properties. Atomicity: A transaction should be treated as a single unit of operation which means either the entire sequence of operations is successful or unsuccessful. Consistency: This represents the consistency of the referential integrity of the database, unique primary keys in tables etc. Isolation: There may be many transactions processing with the same data set at the same time, each transaction should be isolated from others to prevent data corruption. Durability: Once a transaction has completed, the results of this transaction have to be made permanent and cannot be erased from the database due to system failure. Two-phase locking is the most common transaction concurrency control method in DBMSs, used to provide both serializability and recoverability for correctness. 阅读全文...

2015-10-23

git_md_snippet

MarkdownLink(mdlink).sublime-snippet 12345678<snippet> <content><![CDATA[[${1:Display_Text}](${2:http://example.com/} ${3:"$2"})]]></c... 阅读全文...

2015-10-23

spring_jdbc

JdbcTemplate the central framework class that manages all the database communication and exception handling. Instances of the JdbcTemplate class are threadsafe once configured. So you can configure a single instance of a JdbcTemplate and then safely inject this shared reference into multiple DAOs. A common practice when using the JdbcTemplate class is to configure a DataSource in your Spring configuration file, and then dependency-inject that shared DataSource bean into your DAO classes, and the JdbcTemplate is created in the setter for the DataSource. reference: jdbc_spring 阅读全文...