davepkennedy

package io.github.davepkennedy

import scala.annotation.tailrec

object ThreeSum {
  def parseInt (s: String): Option[Int] = try {
    Some (java.lang.Integer.parseInt(s))
  } catch {
    case e: NumberFormatException => None
  }

davepkennedy

def from (i: Int): Stream[Int] = i #:: from(i+1)
val nats = from(0)
val fb = nats map {
  n =>
    if (n % 15 == 0) "fizzbuzz"
    else if (n % 3 == 0) "fizz"
    else if (n % 5 == 0) "buzz"
    else n.toString
}
fb.take(20) foreach println

davepkennedy

import scala.annotation.tailrec
import scala.util.Random

def shuffle (values: List[Int]): List[Int] = {
  val r = new Random()
  
  @tailrec
  def shuffle0 (values: List[Int], accum: List[Int] = List.empty): List[Int] = values match {
    case List(x) => x :: accum
    case h :: t =>

davepkennedy

#include <iostream>
#include <cstdlib>

using namespace std;

// From http://stackoverflow.com/questions/2509679/how-to-generate-a-random-number-from-within-a-range
long random_at_most(long max) {
    unsigned long
    // max <= RAND_MAX < ULONG_MAX, so this is okay.
    num_bins = (unsigned long) max + 1,

davepkennedy

CGContextRef fromImage(NSImage* image)
{
    CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();
    NSSize size = [image size];
    CGContextRef contextRef = CGBitmapContextCreate(NULL, size.width, size.height, 8, 0, colorSpace, kCGImageAlphaPremultipliedLast);
    NSGraphicsContext *graphicsContext = [NSGraphicsContext graphicsContextWithCGContext:contextRef flipped:NO];
    
    NSGraphicsContext* currentContext = [NSGraphicsContext currentContext];
    [NSGraphicsContext setCurrentContext:graphicsContext];
    [image drawInRect:NSMakeRect(0, 0, size.width, size.height)];

davepkennedy

#include <stdio.h>

#define LEFT(x) (2*(x)+1)
#define RIGHT(x) (2*(x)+2)
#define PARENT(x) (((x)-1)/2)

void swap (int* a, int i, int j) {
    int t = a[i];
    a[i] = a[j];
    a[j] = t;

davepkennedy

def sumProbabilities[U] (options: Seq[(Int, () => U)]): Int = {
    options.map {case (p, f) => p}.sum
  }
  def roughly [U] (chance: Int) (f: => U) = chance -> (() => f)

  def chancesOf [U] (options: (Int, () => U)*): () => Option[U] = {
    type Chance = PartialFunction[Int,Option[U]]
    val fallback: Chance = {
      case x => None
    }

davepkennedy

Swap two numbers without an intermediate variable. Still takes as many statement as with one though…

Consider a = 5, b = 10
a = b0101
b = b1010

a = a ^ b -> b0101 ^ b1010 -> a = b1111 (15)
b = a ^ b -> b1111 ^ b1010 -> b = b0101 (5)
a = a ^ b -> b1111 ^ b0101 -> a = b1010 (10)

davepkennedy

def max (a, b):
  c = a-b
  k = (c >> 31) & 1
  return a - k * c

davepkennedy

//
//  GLView.h
//
//  Created by Dave Kennedy on 11/09/2016.
//
//

#import <Cocoa/Cocoa.h>
#import <GLKit/GLKit.h>