alexland

/**
 * Solves the n-Queen puzzle in O(n!)
 * Let p[r] be the column of the queen on the rth row (must be exactly 1 queen per row)
 * There also must be exactly 1 queen per column and hence p must be a permuation of (0 until i)
 * There must be n distinct (col + diag) and n distinct (col - diag) for each queen (else bishop attacks)
 * @return a Vector p of length n such that p[i] is the column of the queen on the ith row
 */
def nQueens(n: Int) = (0 until n).permutations filter {p =>   
  p.zipWithIndex.flatMap{case (c, d) => Seq(n + c + d, c - d)}.distinct.size == 2*n  
}

alexland

Magic words:

psql -U postgres

Most \d commands support additional param of __schema__.name__ and accept wildcards like *.*

• \q: Quit/Exit
• \c __database__: Connect to a database
• \d __table__: Show table definition including triggers

alexland

#!/bin/bash

#------------------------------------------------------------------------------
# Name:    sbtmkdirs
# Purpose: Create an SBT project directory structure with a few simple options.
# Author:  Alvin Alexander, http://alvinalexander.com
# Info:    http://alvinalexander.com/sbtmkdirs
# License: Creative Commons Attribution-ShareAlike 2.5 Generic
#          http://creativecommons.org/licenses/by-sa/2.5/
#------------------------------------------------------------------------------

alexland

# Bulk convert shapefiles to geojson using ogr2ogr
# For more information, see http://ben.balter.com/2013/06/26/how-to-convert-shapefiles-to-geojson-for-use-on-github/

# Note: Assumes you're in a folder with one or more zip files containing shape files
# and Outputs as geojson with the crs:84 SRS (for use on GitHub or elsewhere)

#geojson conversion
function shp2geojson() {
  ogr2ogr -f GeoJSON -t_srs crs:84 "$1.geojson" "$1.shp"
}

alexland

package operator

object FunctionalPipeline {
  class PipedObject[T] private[Functional] (value:T)
    {
      def |>[R] (f : T => R) = f(this.value)
    }
    implicit def toPiped[T] (value:T) = new PipedObject[T](value)
}

alexland

#Newbie programmer
def factorial(x):
    if x == 0:
        return 1
    else:
        return x * factorial(x - 1)
print factorial(6)


#First year programmer, studied Pascal