Merge Strings

1. Given a, b two files, each store 5 billion URLs, each URL accounted for 64 bytes, memory limit is 4G, let you find a, b file common URL? Scenario 1: The size of each file can be estimated to be 50gx64=320g, far larger than the memory limit of 4G. So it is not possible to fully load it into memory processing. 　　Consider adopting a divide-and-conquer approach. s traverses file A, asks for each URL, and then stores the URL to 1000 small files (recorded) based on the values obtained. This ...

The sorting algorithm can be divided into internal sorting and external sorting. The internal sorting is to sort the data records in the memory, while the external sorting is because the sorting data is very large, so it can not hold all the sorting records at a time. In the sorting process, it needs to access the external memory. Common internal sorting algorithms are: Insert sort, Hill sort, Select sort, Bubble sort, Merge sort, Quick sort, Heap sort, Base sort and so on. This article will introduce the above eight sorting algorithm in turn. Algorithm 1: insert sort Insert sort diagram Insert sort is one of the most simple and intuitive sorting algorithm, it's work ...

MapReduce: Simple data processing on large cluster

We find that services that apply Windows Azure tables will be affected when partitionkey or Rowkey contain a "%" character. APIs affected by this include: Get entity, Merge entity, Update entity, Delete entity, insert or Merge entity, and API for insert or replace entity. If any of the above APIs is invoked with its par ...

The front has written a big frame, seems a little general, because there is no point of the graphic analysis. Recently used a more table, this article specifically on the table readability to make a systematic summary, by the way http://www.aliyun.com/zixun/aggregation/16911.html "> Readability-framework updated to v1.1. The following figure: The history of the retrospective table (table), the earliest designers like to use a table layout, because the visual simple intuitive, from ...

Working with text is a common usage of the MapReduce process, because text processing is relatively complex and processor-intensive processing. The basic word count is often used to demonstrate Haddoop's ability to handle large amounts of text and basic summary content. To get the number of words, split the text from an input file (using a basic string tokenizer) for each word that contains the count, and use a Reduce to count each word. For example, from the phrase the quick bro ...

MD5 is the most common cryptographic algorithm used in Web applications. Since the MD5 is irreversible, the ciphertext after MD5 calculation can not get the original text through the reverse algorithm. The intention of using MD5 encrypted text passwords in Web applications is to prevent the passwords stored in the database from being compromised and then being directly acquired. However, the attackers not only have a large number of password dictionaries, but also set up a lot of MD5 original/ciphertext control database, can quickly find common password MD5 ciphertext, is the efficient way to decipher MD5 ciphertext. However, the number of MD5 ciphertext ...

The greatest fascination with large data is the new business value that comes from technical analysis and excavation. SQL on Hadoop is a critical direction. CSDN Cloud specifically invited Liang to write this article, to the 7 of the latest technology to do in-depth elaboration. The article is longer, but I believe there must be a harvest. December 5, 2013-6th, "application-driven architecture and technology" as the theme of the seventh session of China Large Data technology conference (DA data Marvell Conference 2013,BDTC 2013) before the meeting, ...

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Many mobile music applications from this year began to enter the merger shuffle period. 　　At the beginning of the early shrimp music by Alibaba acquisition, a large wave of mergers and acquisitions in succession. Over the two days, two of acquisitions have provoked renewed attention to the use of mobile music. In Saturday, media reports said cool music was sold to an offshore company named Music Corporation in nearly billion dollars. Another message comes from Alibaba's second shot, there are media reports that Alibaba has strategic investment every day, but according to Tencent technology to every day beautiful insiders ...