jboner

Latency Comparison Numbers (~2012)
----------------------------------
L1 cache reference                           0.5 ns
Branch mispredict                            5   ns
L2 cache reference                           7   ns                      14x L1 cache
Mutex lock/unlock                           25   ns
Main memory reference                      100   ns                      20x L2 cache, 200x L1 cache
Compress 1K bytes with Zippy             3,000   ns        3 us
Send 1K bytes over 1 Gbps network       10,000   ns       10 us
Read 4K randomly from SSD*             150,000   ns      150 us          ~1GB/sec SSD

digitaljhelms

Branching

Quick Legend

Description, Instructions, Notes

Instance	Branch

psayre23

Below are the Big O performance of common functions of different Java Collections.


List                 | Add  | Remove | Get  | Contains | Next | Data Structure
---------------------|------|--------|------|----------|------|---------------
ArrayList            | O(1) |  O(n)  | O(1) |   O(n)   | O(1) | Array
LinkedList           | O(1) |  O(1)  | O(n) |   O(n)   | O(1) | Linked List
CopyOnWriteArrayList | O(n) |  O(n)  | O(1) |   O(n)   | O(1) | Array

poindextrose

package main

import (
	"fmt"
	"time"

	"google.golang.org/cloud/storage"
)

const (

vasanthk

System Design Cheatsheet

Picking the right architecture = Picking the right battles + Managing trade-offs

Basic Steps

1. Clarify and agree on the scope of the system

• User cases (description of sequences of events that, taken together, lead to a system doing something useful)
  • Who is going to use it?
  • How are they going to use it?

blacklee

ffmpeg -i input.mp4 -s hd480 -c:v libx264 -crf 23 -c:a aac -strict -2 output.mp4

remen

import com.fasterxml.jackson.databind.JsonNode
import com.fasterxml.jackson.databind.ObjectMapper
import com.fasterxml.jackson.module.kotlin.KotlinModule

fun main(args: Array<String>) {
    val jsonString : String = """
{
  "authors" : [
    {
      "name" : "Kalle Jönsson",

sharmaeklavya2

Competitive Programming Syllabus

Geometry

• Graham Scan algorithm for Convex Hull O(n * log(n))
• Online construction of 3-D convex hull in O(n^2)
• Bentley Ottmann algorithm to list all intersection points of n line segments in O((n + I) * logn)
  • Suggested Reading - http://softsurfer.com/Archive/algorithm_0108/algorithm_0108.htm
• Rotating Calipers Technique
  • Suggested Reading - http://cgm.cs.mcgill.ca/~orm/rotcal.html

• Problems - Refer the article for a list of problems which can be solved using Rotating Calipers technique.

martinheld

JWT Kong Example

• Get and Start Kong and Co

git clone [email protected]:Mashape/docker-kong.git
cd docker-kong/compose
docker-compose up

• Create Kong API Route

jsgao0

package com.jsgao.bean;

import java.security.InvalidKeyException;
import java.security.Key;
import java.security.KeyFactory;
import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.NoSuchAlgorithmException;
import java.security.NoSuchProviderException;
import java.security.PrivateKey;