manhdaovan

/**
 * `benchmark` function took:
 * scala -nc SplitString.scala  14.71s user 0.50s system 274% cpu 5.532 total
 * on MacbookPro Late 2012 (Core i5 2.5, DDR3 8GB @1600)
 */
object SplitString {
  def split(string: String): (String, String) = {
    def loop(chars: List[Char], upper: String, lower: String): (String, String) =
      chars match {
        case Nil => (upper, lower)

manhdaovan

/* Remove duplicate rows on table by simple query.
   Repeate until no more query is removed */

delete from shop_product_price 
       where id in 
       (select tmp.id from 
        (select *, count(*) as num from shop_product_price 
                                   group by shop_id, product_id, price, min_quantity, shipping_fee 
                                   having num >= 2) as tmp);

manhdaovan

def string_2array(s)
  s.split('')
end

# return 1 if s2 > s1
# return 0 if s2 == s1
# return -1 if s2 < s1
def my_compare(s1, s2)
  downcase_letters = ' aàáảãạăằắẳẵặâầấẩẫậbcdđeèéẻẽẹêềếểễệfghiìíỉĩịjklmnoòóỏõọôồốổỗộơờớởỡợpqrstuùúủũụưừứửữựvwxyỳýỷỹỵz'.freeze
  upcase_letters = 'AÀÁẢÃẠĂẰẮẲẴẶÂẦẤẨẪẬBCDĐEÈÉẺẼẸÊỀẾỂỄỆFGHIÌÍỈĨỊJKLMNOÒÓỎÕỌÔỒỐỔỖỘƠỜỚỞỠỢPQRSTUÙÚỦŨỤƯỪỨỬỮỰVWXYỲÝỶỸỴZ'.freeze

manhdaovan

# Calculate number of Similar Numbers
# 112 has 112, 121, 211 (3 similar numbers)
# 100 has 100 (1 similar number)
# Given integer a (1 <= a <= 2^32)
# Calculate number of similar numbers of a

def permute(n)
  return 1 if n == 0
  (1..n).reduce(:*)
end

manhdaovan

// Merge table cell by cell value,
// dependent or independent to other column
// jQuery is required.

// Eg: Table has 2 col: Date and Fullname
// |----------------------------|
// |  Date        |  Fullname   |
// |--------------|-------------|
// |  2012/11/01  |  ManhDV     |
// |--------------|-------------|

manhdaovan

NGINX Tuning For Best Performance

For this configuration you can use web server you like, i decided, because i work mostly with it to use nginx.

Generally, properly configured nginx can handle up to 400K to 500K requests per second (clustered), most what i saw is 50K to 80K (non-clustered) requests per second and 30% CPU load, course, this was 2 x Intel Xeon with HyperThreading enabled, but it can work without problem on slower machines.

You must understand that this config is used in testing environment and not in production so you will need to find a way to implement most of those features best possible for your servers.

• Stable version NGINX (deb/rpm)

manhdaovan

# You have 2 project as:
# /var/www/html/laravel_app, and
# /var/www/html/wordpress_app
# You want to access laravel app as default except blog in url.
# Eg: http://example.com or http://example.com/controller-name
# but when http://example.com/blog, it point to wordpress app.

server {
  listen 80;
  server_name example.com;

manhdaovan

#!/bin/bash

# Create 2GB RAM disk
diskutil erasevolume HFS+ "ramdisk" `hdiutil attach -nomount ram://4194304`

# Install mysql to above ramdisk, with no password
mysqld --initialize-insecure --log-error-verbosity --user=`whoami` --basedir="$(brew --prefix mysql)" --datadir=/Volumes/ramdisk/mysql --tmpdir=/tmp

# Stop current mysql if existing
mysql.server stop

manhdaovan

# Usage: delete_local_branch number_of_weeks_ago
# Eg: delete_local_branch 4

function delete_local_branch() {
  for k in $(git branch | sed /\*/d); do
    if [ -n "$(git log -1 --before='$1 week ago' -s $k)" -a "$k" != "develop" -a "$k" != "master" -a "$k" != "staging" ]; then
      echo "Delete $k"
      git branch -D $k
    fi
  done

manhdaovan

# Download file from target server via proxy server using scp command
# Usage: scp_download_file /path/to/file/in/target/server

function scp_download_file(){
  scp -o "ProxyCommand ssh user@proxy_server_domain_or_ip -W %h:%p" user@target_server_domain_or_ip:$1 ~/Downloads/
}