Tutorial by Examples: b

We can do two things to improve the simple and sub-optimal disjoint-set subalgorithms: Path compression heuristic: findSet does not need to ever handle a tree with height bigger than 2. If it ends up iterating such a tree, it can link the lower nodes directly to the root, optimizing future trav...

You can calculate a number in the Fibonacci sequence using recursion. Following the math theory of F(n) = F(n-2) + F(n-1), for any i > 0, // Returns the i'th Fibonacci number public int fib(int i) { if(i <= 2) { // Base case of the recursive function. // i is either 1...

1. Target a device by serial number Use the -s option followed by a device name to select on which device the adb command should run. The -s options should be first in line, before the command. adb -s <device> <command> Example: adb devices List of devices attached emulator-55...

HTML also provides the tables with the <thead>, <tbody>, <tfoot>, and <caption> elements. These additional elements are useful for adding semantic value to your tables and for providing a place for separate CSS styling. When printing out a table that doesn't fit onto one (pa...

using (new Sitecore.SecurityModel.SecurityDisabler()) { var item = Sitecore.Context.Database.GetItem("/sitecore/content/home"); }

NSError *e = nil; NSString *jsonString = @"[{\"id\": \"1\", \"name\":\"sam\"}]"; NSData *data = [jsonString dataUsingEncoding:NSUTF8StringEncoding]; NSArray *jsonArray = [NSJSONSerialization JSONObjectWithData: data options: NSJSONReadingMutabl...

Useful if your program is outputting web pages along the way. from http.server import HTTPServer, CGIHTTPRequestHandler import webbrowser import threading def start_server(path, port=8000): '''Start a simple webserver serving path on port''' os.chdir(path) httpd = HTTPServer((''...

Rust's #[path] attribute can be used to specify the path to search for a particular module if it is not in the standard location. This is typically discouraged, however, because it makes the module hierarchy fragile and makes it easy to break the build by moving a file in a completely different dire...

Say you have implemented some logic to detect attempts to modify an object in the database while the client that submitted changes didn't have the latest modifications. If such case happens, you raise a custom exception ConfictError(detailed_message). Now you want to return an HTTP 409 (Confict) st...

Creating empty deque: dl = deque() # deque([]) creating empty deque Creating deque with some elements: dl = deque([1, 2, 3, 4]) # deque([1, 2, 3, 4]) Adding element to deque: dl.append(5) # deque([1, 2, 3, 4, 5]) Adding element left side of deque: dl.appendleft(0) # deque([0, 1, 2, ...

A basic User Schema: var mongoose = require('mongoose'); var userSchema = new mongoose.Schema({ name: String, password: String, age: Number, created: {type: Date, default: Date.now} }); var User = mongoose.model('User', userSchema); Schema Types.

Often times you will see an exception Anti forgery token is meant for user "" but the current user is "username" This is because the Anti-Forgery token is also linked to the current logged-in user. This error appears when a user logs in but their token is still linked to bein...

Seaborn is a wrapper around Matplotlib that makes creating common statistical plots easy. The list of supported plots includes univariate and bivariate distribution plots, regression plots, and a number of methods for plotting categorical variables. The full list of plots Seaborn provides is in thei...

CSS ul { list-style: none; counter-reset: list-item-number; /* self nesting counter as name is same for all levels */ } li { counter-increment: list-item-number; } li:before { content: counters(list-item-number, ".") " "; /* usage of counters() function means val...

In the example of a message bubble illustrated below: the corners of the image should remain unchanged which is specified by UIEdgeInsets, but the borders and center of the image should expand to cover the new size. let insets = UIEdgeInsetsMake(12.0, 20.0, 22.0, 12.0) let image = UIImage(na...

<div tabindex="0">Some button</div> Note: Try to use a native HTML button or an a tag where appropriate.

<button tabindex="-1">This button will not be reachable by tab</button> The element will be removed from the tabbing order but will still be focusable.

<div tabindex="2">Second</div> <div tabindex="1">First</div> Positive values will insert the element at the tabbing order position of its respective value. Elements without preference (i.e. tabindex="0" or native elements such as button and a...

We can optimize a simple xor function for only architectures that support unaligned reads/writes by creating two files that define the function and prefixing them with a build constraint (for an actual example of the xor code which is out of scope here, see crypto/cipher/xor.go in the standard libra...

This is a simple but robust core-data set-up for iOS 10+. There are exactly two way to access core-data: viewContext. The viewContext can only be used from the main thread, and only for reading. strong enqueueCoreDataBlock. All writing should be done using enqueueCoreDataBlock. There is no ne...