GurdeepSS

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

GurdeepSS

class Solution {
public:
    int maxSubArray(int A[], int n) {
        if(n<=0)
            return 0;
        int maxSum = A[0];
        int sum = A[0];
        for(int i = 1; i<n; ++i)
        {
            if(sum < 0) // no positive gain for following numbers

GurdeepSS

#!/usr/bin/env python
 
"""Basic Python Cheat Sheet by Filip Kral on 2015/02/16"""
 
"""
Python is a cross-platform, interpreted, object-oriented programming language.
That means you can run it on Linux, Windows, Mac, and other platforms,
you don't need to compile your code to execute it because it is compiled on
the fly, and you can use classes and objects.

GurdeepSS

#!/usr/bin/env python
 
"""Basic Python Cheat Sheet by Filip Kral on 2015/02/16"""
 
"""
Python is a cross-platform, interpreted, object-oriented programming language.
That means you can run it on Linux, Windows, Mac, and other platforms,
you don't need to compile your code to execute it because it is compiled on
the fly, and you can use classes and objects.

GurdeepSS

#!/usr/bin/env python
 
"""Basic Python Cheat Sheet by Filip Kral on 2015/02/16"""
 
"""
Python is a cross-platform, interpreted, object-oriented programming language.
That means you can run it on Linux, Windows, Mac, and other platforms,
you don't need to compile your code to execute it because it is compiled on
the fly, and you can use classes and objects.

GurdeepSS

/*============================================================================
Name        : LinkedList.java
Author      : Eric Swanson
Date		: Sep 7, 2011
Version     : 
Description : 

Copyright (C) 2011 Eric Swanson

    This program is free software: you can redistribute it and/or modify

GurdeepSS

/*============================================================================
Name        : LinkedList.java
Author      : Eric Swanson
Date		: Sep 7, 2011
Version     : 
Description : 

Copyright (C) 2011 Eric Swanson

    This program is free software: you can redistribute it and/or modify

GurdeepSS

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?

GurdeepSS

Docker + Apache Tomcat + JSP

This article describes how to deploy a JSP website using Docker, Apache Tomcat.

Directory structure

I found a way to make a minimal JSP web application from scratch, without any IDE. (ref: https://www.youtube.com/watch?v=JEBR_KJdzSk)

First, organize your working directory like this:

GurdeepSS

// Setup the LDAP client (normally done via Spring context file).
LdapContextSource contextSource = new LdapContextSource();
contextSource.setUrl("ldap://adserver.mycompany.com:3268");
contextSource.setBase("DC=AD,DC=MYCOMPANY,DC=COM");
contextSource.setUserDn("readonlyuser@ad.mycompany.com");
contextSource.setPassword("password1");
contextSource.afterPropertiesSet();

LdapTemplate ldapTemplate = new LdapTemplate(contextSource);
ldapTemplate.afterPropertiesSet();