lqt0223’s gists

lqt0223 / promise.js

Last active May 30, 2017 12:11

Promise implementation

	// Promise Implemenetation

	// SOME CONSTANT
	var https = require('https')

	var URL1 = "https://jsonplaceholder.typicode.com/posts?userId="
	var URL2 = "https://jsonplaceholder.typicode.com/posts?id="

	// Phase 1: make function in 'then' deferred, and callback with resolved data later

lqt0223 / sync.html

Last active May 29, 2017 10:13

The difference between 'sync' event and 'sync' attribute in Backbone

	<html lang="en">
	<head>
	<script src="https://cdn.bootcss.com/jquery/3.2.1/jquery.js"></script>
	<script src="https://cdn.bootcss.com/underscore.js/1.8.3/underscore.js"></script>
	<script src="https://cdn.bootcss.com/backbone.js/1.3.3/backbone.js"></script>
	</head>
	<body>
	<script>

	// The difference between 'sync' event and 'sync' attribute in Backbone

lqt0223 / playground.html

Last active May 29, 2017 10:10

Backbone playground

	<!DOCTYPE html>
	<html lang="en">
	<head>
	<meta charset="UTF-8">
	<title>Document</title>
	<script src="https://cdn.bootcss.com/jquery/3.2.1/jquery.js"></script>
	<script src="https://cdn.bootcss.com/underscore.js/1.8.3/underscore.js"></script>
	<script src="https://cdn.bootcss.com/backbone.js/1.3.3/backbone.js"></script>
	</head>
	<body>

lqt0223 / filter_object.js

Created April 27, 2017 02:48

22 Filter an object and return key-value pairs that pass the filter

	function filterObject(obj, fn){
	return Object.keys(obj).filter((key) => {
	var e = obj[key];
	return fn(e);
	}).map((e) => {
	return {
	key: e,
	value: obj[e]
	};
	});

lqt0223 / lcs.js

Created April 11, 2017 15:14

21 Longest common subsequence in JavaScript

	var str1 = "XMJYAUZ";
	var str2 = "MZJAWXU";
	var result = lcs(str1, str2);
	console.log(result);

	// result is { maxLength: 4, sequence: 'MJAU' }

	function lcs(str1, str2){
	var maxLength = 0, maxCol = 0, maxRow = 0;
	var sequence = "";

lqt0223 / knapsack.js

Created April 11, 2017 11:52

20 0-1 Knapsack problem in JavaScript

	/* 0-1 knapsack problem

	For an overall introduction to knapsack problem, see https://en.wikipedia.org/wiki/Knapsack_problem

	Function name: knapsack
	Param:
	items: an array of {w: v:} (where 'w' stands for weight, and 'v' stands for value)
	capacity: a positive integer number
	Will return max sum value that can reach, and the chosen subset to add up to the value.

lqt0223 / bitwise.js

Created April 9, 2017 12:02

19 Bitwise operation and utilities

	// bitwise operation and utilities

	// Left shift by 1, will multiply the number by 2
	console.log(2 << 1); // return 4

	// Right shift by 1, will divide the number by 2.
	// In JavaScript, the decimal part will be floored
	console.log(2 >> 1); // return 1
	console.log(3 >> 1); // return 1

lqt0223 / graph.js

Last active April 8, 2017 16:06

18 Weighted & Directional Graph and Dijkstra's Algorithm in JavaScript

	// Weighted directional graph implementation and Dijkstra's algorithm

	class Graph {

	constructor() {
	this.vertices = [];
	this.edges = [];
	}

	// add a sequence of vertices to the graph

lqt0223 / deepcopy.js

Last active April 7, 2017 03:49

17 Deep copy in JavaScript

	// You are welcome to have a test on this function to check if it supports deep copy for very complex nested objects.
	function deepCopy(o){
	if(typeof o === "object" && o !== null){
	var _o = new o.constructor();
	for(var k in o){
	_o[k] = deepCopy(o[k]);
	}
	return _o;
	}else{
	return o;

lqt0223 / p&c.js

Last active December 21, 2017 02:46

16 Permutation and Combination in JavaScript

	/*

	Permutation in mathmatics stands for all possible order for a set.
	Combination in mathmatics stands for all possible ways of selecting items from a set.
	Find more at
	https://en.wikipedia.org/wiki/Permutation
	https://en.wikipedia.org/wiki/Combination

	*/

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