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最好金龟换酒，这是一本豆瓣高分烂书
买这本书的时候，其实没怎么多想。或者说是没想。。。当然这貌似也是我的风格。。。豆瓣上那么高的评分，加上这么赞的书名，立刻就买了。寒假回家毕竟是忙的，除了照顾家里的事情，还要出门会会朋友，自然是没有时间看，于是我就不远万里，跨大洲跨大洋的把这书从中国硬是背回到了美国。可是，万万没有想到，这书真是烂呀~~~这其实是一本很普通的游记书记，或者说是游记日记，其实基本全书也就是作者游记的博客。。。恩恩，博客~...
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Leetcode Mode Starts
要开始找工作了，眼看着现在的行情一年不如一年，真是心碎。。。有一种博士毕业，黄花菜都凉了的感觉。。。准备开始找工作了，虽然现在已经很晚了，但是没办法，抓紧开始吧。。。刷题，刷题，刷题，嘻唰唰，嘻唰唰，嘻唰唰，希望不要，泪刷刷，泪刷刷，泪刷刷。今天做了20道easy的题，跪了，好多很简单地感觉都要磨叽半天才能搞出来。肿么破！
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我是一个坚强的人，但我不会翻转二叉树
我是一个坚强的人，我不轻易掉眼泪。不就是个事儿嘛，兵来将挡，水来土掩，有事扛着。但有两次，让我刻骨铭心。一次是本科毕业后，我发现，依旧修不好七大姑八大姨的电脑。另一次是，博士生涯第六年，我发现，仍然不会翻转二叉树。
View ArticleProof of "For convex optimization problems, local minima are global minima."
Probably, everyone in or partially in machine learning or data mining heard about the quote “There is no local minima for convex problem.” Today I would like to show the mathematical proof of this...
View Article最近的生活
最近的生活基本是这样的，刷完这道题，就去洗澡。刷完这道题，就去吃早饭。刷完这道题，就去做中饭。刷完这道题，就去做晚饭。刷完这道题，就去健身房。刷完这道题，就去游泳。然后，到了晚上，发现，这一天，啥都没干。。。
View ArticleFirst-Order Optimality Condition
I will continue the notation I used in previous post.The convex optimization problems are defined as follows: Here, for notational brevity, the convex optimization problems can be expressed in the...
View ArticleSigned Number Representation and Bitwise Operation
Signed Number RepresentationRepresenting numbers is an interesting topic. Intuitively, we can represent the numbers in many different ways. However, when it comes to the digital world, in computer...
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Gradient Descent Essentials
Gradient descent is arguably the most widely used optimization techniques. At least in my personal research, it almost occupied the majority of my research solutions.Gradient descent looks pretty...
View ArticleMultiset
In mathematics, a multiset (or bag) is a generalization of the concept of a set that, unlike a set, allows multiple instances of the multiset’s elements.A multiset is similar to the set concept but...
View ArticleBinomial Coefficient Basics
Binomial CoefficientThe majority content in the following can be found in wikipedia https://en.wikipedia.org/wiki/Binomial_coefficient. Here I would like to highlight some key “basics”...
View ArticleAmazon Research Interview
1st Phone InterviewBriefly introduce your PhD work and some internship experience.Difference between hidden Markov models and linear dynamical system.Coding questions: similar to the Leetcode question:...
View ArticleLyft Interview
Data ChallengeYou are given a 300M dataset (~3,000,000 rows) which includes GPS informations about the passenger’s desired pick-up and drop-off locations and their actual pick-up and drop-off...
View ArticleVatic Labs Interview
HR Phone InterviewIntroduce yourself and your PhD research.Why do you swtich from CS to financial?What’s the most proud thing you have done?
View ArticleNEC Lab Interview
Phone Interview (with about 8-10 people)Briefly introduce your PhD work and some internship experience.Pick one of our papers and discuss the details.People in the lab keep switching the phone and ask...
View ArticleCoursera Interview
Phone InterviewA coding question: You are given a string containing a comma-separated list of tokens. Tokens may have zero length, contain internal commas, or be surrounded by double quotes (“). Write...
View ArticleAncestry Interview
Online coding testA simple string processing problem with some corner cases.
View ArticleMicrosoft Interview
Phone InterviewHave a fair coin and you can flip it many times. Now you are asked to make a Yes-or-No decision based on probabilities: 1/3 chance say “Yes” and 2/3 chance say “No”. How do you flip the...
View ArticleAdobe Research Interview
Phone Interview (with director)Briefly introduce your PhD work and some internship experience.Ask any questions after the director explains the details about Adobe Research.Question: what the problems...
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