SEARCH KEYWORD -- BINARY TREE

  The trap of the performance sweet spot

This post is about JavaScript performance but I would like to start it by telling a story that might seem unrelated to JS. Please bear with me if you don’t like C.A story of a C programmer writing JavaScriptMr. C. is a C programmer as you can probably guess from his name. Today he was asked by his boss to write a very simple function: given an array of numbered 2d points calculate vector sum of all even numbered points... He opens his favorite text editor and quickly types somet...

   C,JavaScript,Sweet spot,Memory,Low level,Trap     2011-11-06 14:45:01

  People Detection Radar [IoT] : Build a Raspberry PI Xandar Kardian IoT People Count Radar

Program Design Purpose: People detection sensors and radars are utilized in various applications across multiple fields such as security and surveillance, healthcare, building automation, smart cities, transportation and autonomous manufacturing systems. This project aims to develop a prototype IoT device for an indoor people counting using the Xandar Kardian people detection radar and a Raspberry Pi. The device will be network-ready and easily integrated with other systems. The Python-based I...

       2024-07-21 08:19:57

  The Essence of Google Dart: Building Applications, Snapshots, Isolates

WÑ–th thousands of programming languages floating around, why is Google introducing Google Dart? What can it possibly add? The short answer: the Google Dart team wanted a language well suited to modern application development, both on the server and the (mobile) client. Some of Dart's features address problems that languages like Java or Javascript have long had. Dart's Snapshots resemble Smalltalk images, allowing (nearly) instant application startup and wi...

   Dart,Google,Client side,Web,Language,Snapshort,Isolate     2011-10-24 11:41:16

  Reset submodule to checkout state in git

Sometimes there would be a submodule or some submodules within one git repository, in some cases the submodule may be out of sync with the checkout state as some files in submodule may be changed unexpectedly. How to reset the submodule to be the same as the original checkout state? Let's take an example that we have a git repository A and there is a submodule called ruby-gems under it. Assuming the submodule at remote origin has commit a. And on our local environment, the repository A has a lat...

   GIT SUBMODULE,GIT RESET     2020-09-05 08:30:57

  PHP: a fractal of bad design

Preface I’m cranky. I complain about a lot of things. There’s a lot in the world of technology I don’t like, and that’s really to be expected—programming is a hilariously young discipline, and none of us have the slightest clue what we’re doing. Combine with Sturgeon’s Law, and I have a lifetime’s worth of stuff to gripe about. This is not the same. PHP is not merely awkward to use, or ill-suited for what I want, or suboptimal, or...

   PHP,Design,Analysis     2012-04-11 13:46:57

  Why (offset, limit) is slow in database select?

Starting from a problem Five years ago when I was working at Tencent, I found that MySQL request speed was very slow in the pagination scenario. With only 100,000 data, a select query on a single machine took about 2-3 seconds. I asked my mentor why, and he asked in return, "In an indexing scenario, what is the time complexity to get the nth largest number in MySQL?" The pursuit of the answer Confirming the scenario Assuming there is an index on the "status" column, a query like "select * from t...

   SLOW,LIMIT,OFFSET,MYSQL     2023-03-12 05:21:02

RECENT