Chen Tong's ideas and writings — notes on software, data science, algorithms, and more.https://cixuuz.github.io/https://cixuuz.github.io/blog/bit-manipulation/https://cixuuz.github.io/blog/bit-manipulation/XOR operation:Sun, 14 Jul 2019 00:00:00 GMThttps://cixuuz.github.io/blog/sync_a_fork/https://cixuuz.github.io/blog/sync_a_fork/Its useful to sync a fork when contributing to open source project.Sun, 17 Mar 2019 00:00:00 GMThttps://cixuuz.github.io/blog/programming-mutation/https://cixuuz.github.io/blog/programming-mutation/因为类型是Mutation的，所以reference和copy就有了区别。如果是reference，那么可能会暴露数据本身，遭到恶意修改，引发安全的问题。下面是一段Java代码，其中有一个 Mutation引起的的bug：Mon, 29 Jan 2018 00:00:00 GMThttps://cixuuz.github.io/blog/ai-constraint-satisfaction-problem/https://cixuuz.github.io/blog/ai-constraint-satisfaction-problem/1. States defined by values of a fixed set of variables from domainSat, 20 Jan 2018 00:00:00 GMThttps://cixuuz.github.io/blog/ai-first-order-logic/https://cixuuz.github.io/blog/ai-first-order-logic/While propositional logic assumes the world contains facts, first-order logic assumes the world contains objects, relations, functions, like natural language.Sat, 20 Jan 2018 00:00:00 GMThttps://cixuuz.github.io/blog/ai-learning-from-obs/https://cixuuz.github.io/blog/ai-learning-from-obs/Problem: decide whether to wait for a table at a restaurant, based on the following attributes:Sat, 20 Jan 2018 00:00:00 GMThttps://cixuuz.github.io/blog/ai-logical-agents/https://cixuuz.github.io/blog/ai-logical-agents/a set of sentences. - inference:deriving new sentences from old - TELL: add new sentences to the knowledge base - ASK: a way to query what is known. The…Sat, 20 Jan 2018 00:00:00 GMThttps://cixuuz.github.io/blog/amazon-ceo-letter-2016/https://cixuuz.github.io/blog/amazon-ceo-letter-2016/To our shareowners: This year, Amazon became the fastest company ever to reach $100 billion in annual sales. Also this year, Amazon Web Services is reaching…Sat, 20 Jan 2018 00:00:00 GMThttps://cixuuz.github.io/blog/system_design_web_crawler/https://cixuuz.github.io/blog/system_design_web_crawler/The Crawler Service processes each page link by doing the following in a loop:Wed, 18 Oct 2017 00:00:00 GMThttps://cixuuz.github.io/blog/lcs_1017/https://cixuuz.github.io/blog/lcs_1017/(no summary)Tue, 17 Oct 2017 00:00:00 GMThttps://cixuuz.github.io/blog/lcs_1015/https://cixuuz.github.io/blog/lcs_1015/(no summary)Sun, 15 Oct 2017 00:00:00 GMThttps://cixuuz.github.io/blog/system_design_tinyurl/https://cixuuz.github.io/blog/system_design_tinyurl/Base10, Base62Thu, 12 Oct 2017 00:00:00 GMThttps://cixuuz.github.io/blog/ml_framework/https://cixuuz.github.io/blog/ml_framework/境界 1：参数可单机存储和更新Sat, 07 Oct 2017 00:00:00 GMThttps://cixuuz.github.io/blog/lcs_1005/https://cixuuz.github.io/blog/lcs_1005/(no summary)Thu, 05 Oct 2017 00:00:00 GMThttps://cixuuz.github.io/blog/programming-multithreading/https://cixuuz.github.io/blog/programming-multithreading/Semaphores: It’s simply a way to limit the number of consumers for a specific resource. For example, to limit the number of simultaneous calls to a database in…Mon, 02 Oct 2017 00:00:00 GMThttps://cixuuz.github.io/blog/ds-feature-engineer/https://cixuuz.github.io/blog/ds-feature-engineer/One of k encoding on an array of lenght kTue, 26 Sep 2017 00:00:00 GMThttps://cixuuz.github.io/blog/interview-ds/https://cixuuz.github.io/blog/interview-ds/Probability/Statistics QuestionsFri, 22 Sep 2017 00:00:00 GMThttps://cixuuz.github.io/blog/distributed_system/https://cixuuz.github.io/blog/distributed_system/Google papers(GFS/BigTable/Spanner/F1)Thu, 21 Sep 2017 00:00:00 GMThttps://cixuuz.github.io/blog/lcs_0918/https://cixuuz.github.io/blog/lcs_0918/(no summary)Mon, 18 Sep 2017 00:00:00 GMThttps://cixuuz.github.io/blog/lcs_0915/https://cixuuz.github.io/blog/lcs_0915/(no summary)Fri, 15 Sep 2017 00:00:00 GMThttps://cixuuz.github.io/blog/lcs_0914/https://cixuuz.github.io/blog/lcs_0914/(no summary)Thu, 14 Sep 2017 00:00:00 GMThttps://cixuuz.github.io/blog/ds-suggest/https://cixuuz.github.io/blog/ds-suggest/Strictly speaking, there is no such thing as “data science” (see What is data science and what is it not? ). See also: Vardi, Science has only two legs:…Wed, 13 Sep 2017 00:00:00 GMThttps://cixuuz.github.io/blog/ds_metrics/https://cixuuz.github.io/blog/ds_metrics/1. What metrics should be used for evaluating a model on an imbalanced data set? (precision + recall or ROC=TPR+FPR)Wed, 13 Sep 2017 00:00:00 GMThttps://cixuuz.github.io/blog/ds_path/https://cixuuz.github.io/blog/ds_path/Machine LearningWed, 13 Sep 2017 00:00:00 GMThttps://cixuuz.github.io/blog/ds_summary/https://cixuuz.github.io/blog/ds_summary/Machine LearningWed, 13 Sep 2017 00:00:00 GMThttps://cixuuz.github.io/blog/lcs_0913/https://cixuuz.github.io/blog/lcs_0913/(no summary)Wed, 13 Sep 2017 00:00:00 GMThttps://cixuuz.github.io/blog/ml_metrics/https://cixuuz.github.io/blog/ml_metrics/1. What metrics should be used for evaluating a model on an imbalanced data set? (precision + recall or ROC=TPR+FPR)Wed, 13 Sep 2017 00:00:00 GMThttps://cixuuz.github.io/blog/lcs_0906/https://cixuuz.github.io/blog/lcs_0906/(no summary)Wed, 06 Sep 2017 00:00:00 GMThttps://cixuuz.github.io/blog/algorithm-leetcode/https://cixuuz.github.io/blog/algorithm-leetcode/2017-10-15Tue, 05 Sep 2017 00:00:00 GMThttps://cixuuz.github.io/blog/algorithm_leetcode/https://cixuuz.github.io/blog/algorithm_leetcode/2017-09-06Tue, 05 Sep 2017 00:00:00 GMThttps://cixuuz.github.io/blog/lcs_0905/https://cixuuz.github.io/blog/lcs_0905/(no summary)Tue, 05 Sep 2017 00:00:00 GMThttps://cixuuz.github.io/blog/lcs_0904/https://cixuuz.github.io/blog/lcs_0904/(no summary)Mon, 04 Sep 2017 00:00:00 GMThttps://cixuuz.github.io/blog/ds-jd/https://cixuuz.github.io/blog/ds-jd/PhD in Computer Science, Computational Linguistics, or related field preferred, or Master’s degree with 2+ years’ of relevant industry experienceSun, 03 Sep 2017 00:00:00 GMThttps://cixuuz.github.io/blog/lcs_0903/https://cixuuz.github.io/blog/lcs_0903/(no summary)Sun, 03 Sep 2017 00:00:00 GMThttps://cixuuz.github.io/blog/lcs_0902/https://cixuuz.github.io/blog/lcs_0902/[37,-34,-48,null,-100,-100,48,null,null,null,null,-54,null,-71,-22,null,null,null,8]Sat, 02 Sep 2017 00:00:00 GMThttps://cixuuz.github.io/blog/lcs_0901/https://cixuuz.github.io/blog/lcs_0901/(no summary)Fri, 01 Sep 2017 00:00:00 GMThttps://cixuuz.github.io/blog/ds-summary/https://cixuuz.github.io/blog/ds-summary/Strictly speaking, there is no such thing as “data science” (see What is data science and what is it not? ). See also: Vardi, Science has only two legs:…Tue, 29 Aug 2017 00:00:00 GMThttps://cixuuz.github.io/blog/java-comparator/https://cixuuz.github.io/blog/java-comparator/做题的时候遇到了sort，想试试Java 8的新语法。于是有了一些研究：Tue, 29 Aug 2017 00:00:00 GMThttps://cixuuz.github.io/blog/lcs_0829/https://cixuuz.github.io/blog/lcs_0829/(no summary)Tue, 29 Aug 2017 00:00:00 GMThttps://cixuuz.github.io/blog/lcs_0827/https://cixuuz.github.io/blog/lcs_0827/same with 51Sun, 27 Aug 2017 00:00:00 GMThttps://cixuuz.github.io/blog/java-tutorial/https://cixuuz.github.io/blog/java-tutorial/(no summary)Thu, 24 Aug 2017 00:00:00 GMThttps://cixuuz.github.io/blog/lcs_0824/https://cixuuz.github.io/blog/lcs_0824/terminal case: null - TrueThu, 24 Aug 2017 00:00:00 GMThttps://cixuuz.github.io/blog/java-pass-by-value/https://cixuuz.github.io/blog/java-pass-by-value/java 传值还是引用Wed, 23 Aug 2017 00:00:00 GMThttps://cixuuz.github.io/blog/lcs_0823/https://cixuuz.github.io/blog/lcs_0823/(no summary)Wed, 23 Aug 2017 00:00:00 GMThttps://cixuuz.github.io/blog/lcs_0822/https://cixuuz.github.io/blog/lcs_0822/(no summary)Tue, 22 Aug 2017 00:00:00 GMThttps://cixuuz.github.io/blog/python-numpy/https://cixuuz.github.io/blog/python-numpy/(no summary)Mon, 21 Aug 2017 00:00:00 GMThttps://cixuuz.github.io/blog/readings_in_database_systems/https://cixuuz.github.io/blog/readings_in_database_systems/Background introduced by Michael StonebrakerMon, 21 Aug 2017 00:00:00 GMThttps://cixuuz.github.io/blog/database-index/https://cixuuz.github.io/blog/database-index/数据库索引与事务管理Sun, 20 Aug 2017 00:00:00 GMThttps://cixuuz.github.io/blog/js-es6/https://cixuuz.github.io/blog/js-es6/(no summary)Sun, 20 Aug 2017 00:00:00 GMThttps://cixuuz.github.io/blog/mysql-high-availability/https://cixuuz.github.io/blog/mysql-high-availability/MySQL高可用方面，目前业界主流依然是基于异步复制的技术，例如Keepalived、MHA、ZooKeeper等，要求数据强一致的场景逐步开始使用分布式协议，这方面的典型代表有PXC、Group Replication、TiDB。下面我们就重点来说说keepalived、MHA和PXC这几种大家用得比较多的架构。Sun, 20 Aug 2017 00:00:00 GMThttps://cixuuz.github.io/blog/statistical-learning/https://cixuuz.github.io/blog/statistical-learning/Statistical LearningSun, 20 Aug 2017 00:00:00 GMThttps://cixuuz.github.io/blog/lcs_0815/https://cixuuz.github.io/blog/lcs_0815/(no summary)Tue, 15 Aug 2017 00:00:00 GMThttps://cixuuz.github.io/blog/lcs_0813/https://cixuuz.github.io/blog/lcs_0813/(no summary)Sun, 13 Aug 2017 00:00:00 GMThttps://cixuuz.github.io/blog/lcs_0812/https://cixuuz.github.io/blog/lcs_0812/(no summary)Sat, 12 Aug 2017 00:00:00 GMThttps://cixuuz.github.io/blog/summary_leetcode_1/https://cixuuz.github.io/blog/summary_leetcode_1/Pure math. Median definition is the median is used for dividing a set into two equal length subsets, that one subset is always greater than the other.Wed, 09 Aug 2017 00:00:00 GMThttps://cixuuz.github.io/blog/lc_102/https://cixuuz.github.io/blog/lc_102/Pure math. Median definition is the median is used for dividing a set into two equal length subsets, that one subset is always greater than the other.Tue, 08 Aug 2017 00:00:00 GMThttps://cixuuz.github.io/blog/airflow_config/https://cixuuz.github.io/blog/airflow_config/sudo apt-get updateSun, 30 Jul 2017 00:00:00 GMThttps://cixuuz.github.io/blog/lc_262/https://cixuuz.github.io/blog/lc_262/select t2.day, round(ifnull(t1.c, 0) / t2.c, 2) as ‘cancellation rate’Sun, 30 Jul 2017 00:00:00 GMThttps://cixuuz.github.io/blog/lc_574/https://cixuuz.github.io/blog/lc_574/select c2.nameSun, 30 Jul 2017 00:00:00 GMThttps://cixuuz.github.io/blog/lc_577/https://cixuuz.github.io/blog/lc_577/select e.name, b.bonusSun, 30 Jul 2017 00:00:00 GMThttps://cixuuz.github.io/blog/lc_580/https://cixuuz.github.io/blog/lc_580/select d.dept\name, count(s.student\id) as student\numberSun, 30 Jul 2017 00:00:00 GMThttps://cixuuz.github.io/blog/lc_584/https://cixuuz.github.io/blog/lc_584/select distinct nameSun, 30 Jul 2017 00:00:00 GMThttps://cixuuz.github.io/blog/lc_175/https://cixuuz.github.io/blog/lc_175/175. Combine Two TablesSun, 25 Jun 2017 00:00:00 GMThttps://cixuuz.github.io/blog/lc_176/https://cixuuz.github.io/blog/lc_176/176. Second Highest SalarySun, 25 Jun 2017 00:00:00 GMThttps://cixuuz.github.io/blog/lc_177/https://cixuuz.github.io/blog/lc_177/177. Nth Highest SalarySun, 25 Jun 2017 00:00:00 GMThttps://cixuuz.github.io/blog/lc_178/https://cixuuz.github.io/blog/lc_178/178. Rank ScoresSun, 25 Jun 2017 00:00:00 GMThttps://cixuuz.github.io/blog/lc_180/https://cixuuz.github.io/blog/lc_180/178. Rank ScoresSun, 25 Jun 2017 00:00:00 GMThttps://cixuuz.github.io/blog/hardware-raid-principles/https://cixuuz.github.io/blog/hardware-raid-principles/1. <https://en.wikipedia.org/wiki/HammingcodeSun, 07 May 2017 00:00:00 GMThttps://cixuuz.github.io/blog/java-path/https://cixuuz.github.io/blog/java-path/如果你不知道什么是for/while lopp、不知道什么是list，建议你先上这门公开课：Sun, 07 May 2017 00:00:00 GMThttps://cixuuz.github.io/blog/four-types-financial-statements/https://cixuuz.github.io/blog/four-types-financial-statements/Statement of Financial Position, also known as the Balance Sheet, presents the financial position of an entity at a given date. It is comprised of the…Tue, 25 Apr 2017 00:00:00 GMThttps://cixuuz.github.io/blog/deep_learning_behind_tensorflow_distribute_principles_and_framework/https://cixuuz.github.io/blog/deep_learning_behind_tensorflow_distribute_principles_and_framework/represent word as low dimensional, dense vectorsSat, 22 Apr 2017 00:00:00 GMThttps://cixuuz.github.io/blog/intro-to-xpath/https://cixuuz.github.io/blog/intro-to-xpath/发现一个很好的xpath入门教程Thu, 13 Apr 2017 00:00:00 GMThttps://cixuuz.github.io/blog/notes-for-advices-pythonic-programming/https://cixuuz.github.io/blog/notes-for-advices-pythonic-programming/记录一下自己认为比较有用的片段Tue, 11 Apr 2017 00:00:00 GMThttps://cixuuz.github.io/blog/remote-debug-using-pycharm-on-aws-ec2/https://cixuuz.github.io/blog/remote-debug-using-pycharm-on-aws-ec2/http://www.jianshu.com/p/9b362cdee2abWed, 05 Apr 2017 00:00:00 GMThttps://cixuuz.github.io/blog/python-tips/https://cixuuz.github.io/blog/python-tips/https://zhuanlan.zhihu.com/p/26099601Fri, 31 Mar 2017 00:00:00 GMThttps://cixuuz.github.io/blog/json/https://cixuuz.github.io/blog/json/(no summary)Thu, 30 Mar 2017 00:00:00 GMThttps://cixuuz.github.io/blog/python-profiling/https://cixuuz.github.io/blog/python-profiling/commandline profilingThu, 30 Mar 2017 00:00:00 GMThttps://cixuuz.github.io/blog/all-about-hardware/https://cixuuz.github.io/blog/all-about-hardware/1. http://www.pcgamer.com/hard-drive-vs-ssd-performance/2/Tue, 28 Mar 2017 00:00:00 GMThttps://cixuuz.github.io/blog/how-to-remote-connect-to-postgresql/https://cixuuz.github.io/blog/how-to-remote-connect-to-postgresql/默认情况下，PostgreSQL 是配制成绑定 “localhost”.Sun, 26 Mar 2017 00:00:00 GMThttps://cixuuz.github.io/blog/ai-notes/https://cixuuz.github.io/blog/ai-notes/1. Four different views of AISun, 19 Mar 2017 00:00:00 GMThttps://cixuuz.github.io/blog/bittiger-cs101-notebook-7/https://cixuuz.github.io/blog/bittiger-cs101-notebook-7/POST: post dataMon, 28 Nov 2016 00:00:00 GMThttps://cixuuz.github.io/blog/bellmanford-algorithm/https://cixuuz.github.io/blog/bellmanford-algorithm/There is an unacceptable solution for leetcode Minimum Height Trees due to time limit exceeded. But it’s an algorithm I didn’t know, so record it.Fri, 11 Nov 2016 00:00:00 GMThttps://cixuuz.github.io/blog/bittiger-cs101-notebook-5/https://cixuuz.github.io/blog/bittiger-cs101-notebook-5/is a instance of a running programMon, 07 Nov 2016 00:00:00 GMThttps://cixuuz.github.io/blog/bittiger-cs101-notebook-6/https://cixuuz.github.io/blog/bittiger-cs101-notebook-6/1. InterruptionMon, 07 Nov 2016 00:00:00 GMThttps://cixuuz.github.io/blog/bittiger-cs101-notebook-1/https://cixuuz.github.io/blog/bittiger-cs101-notebook-1/1. know the featuresSat, 05 Nov 2016 00:00:00 GMThttps://cixuuz.github.io/blog/bittiger-cs101-notebook-2/https://cixuuz.github.io/blog/bittiger-cs101-notebook-2/1 HZ = 1 clock timeSat, 05 Nov 2016 00:00:00 GMThttps://cixuuz.github.io/blog/bittiger-cs101-notebook-3/https://cixuuz.github.io/blog/bittiger-cs101-notebook-3/connect by points and write by orderSat, 05 Nov 2016 00:00:00 GMThttps://cixuuz.github.io/blog/bittiger-cs101-notebook-4/https://cixuuz.github.io/blog/bittiger-cs101-notebook-4/load code class and other java base classes such as java.io util …Sat, 05 Nov 2016 00:00:00 GMThttps://cixuuz.github.io/blog/leetcode-239/https://cixuuz.github.io/blog/leetcode-239/OK。终于仍不住要自己开贴记录一下刷题流程了。那么就从今天开始吧，希望今年能把所有的内容都更新起来。Thu, 03 Nov 2016 00:00:00 GMThttps://cixuuz.github.io/blog/database-notebook-01/https://cixuuz.github.io/blog/database-notebook-01/Physical Data Independence: the ability to modify the physical schema without changing the logical schemaSat, 29 Oct 2016 00:00:00 GMThttps://cixuuz.github.io/blog/python-path-1/https://cixuuz.github.io/blog/python-path-1/按, 作为一个Python初学者, Python的格式化语法让众多编程小白追捧, 它的语法糖让代码变得简洁易读, 它的庞大开源库让它在各个领域都能发挥作用. 但我时常感受到这个门槛极低的语言远没有表面上看起来易懂易用. 在Python的学习之路上, 我也时常迷茫于自己是否真正掌握了这门语言.…Sun, 31 Jul 2016 00:00:00 GMThttps://cixuuz.github.io/blog/kaggle-freshman-book-1/https://cixuuz.github.io/blog/kaggle-freshman-book-1/按，本文根据陈驰在tigger kaggle小组中的关于kaggle比赛的微讲座整理的。整理者：Wente Guo(正文部分), EK(QA部分及审核)Mon, 20 Jun 2016 00:00:00 GMThttps://cixuuz.github.io/blog/about-generator-2/https://cixuuz.github.io/blog/about-generator-2/按, 上篇介绍了generator相关的概念. 这篇来探究一下generator相关的操作方法. 以下都是使用Python 2.7.10.Sat, 18 Jun 2016 00:00:00 GMThttps://cixuuz.github.io/blog/about-generator/https://cixuuz.github.io/blog/about-generator/按, 作为一个Python初学者, Python的格式化语法让众多编程小白追捧, 它的语法糖让代码变得简洁易读，它的庞大开源库让它在各个领域都能发挥作用. 但我时常感受到这个门槛极低的语言远没有表面上看起来易懂易用. 在Python的学习之路上, 我也时常迷茫于自己是否真正掌握了这门语言.…Mon, 30 May 2016 00:00:00 GMThttps://cixuuz.github.io/blog/network-centrality/https://cixuuz.github.io/blog/network-centrality/This is one of notes from CS3943/9223 Foundation of Data Science at New York University.Tue, 12 Apr 2016 00:00:00 GMThttps://cixuuz.github.io/blog/precision-recall-fmeasure/https://cixuuz.github.io/blog/precision-recall-fmeasure/This is one of notes from CS3943/9223 Foundation of Data Science at New York University.Thu, 31 Mar 2016 00:00:00 GMThttps://cixuuz.github.io/blog/mathjax-with-jekyll/https://cixuuz.github.io/blog/mathjax-with-jekyll/It is easy and simple to build a website with Jekyll. An advantage of using Jekyll is the ability to support MathJax, which means I can write LaTeX-like…Wed, 30 Mar 2016 00:00:00 GMT