yutaono

trait Monoid[A] {
  def mappend(a: A, b: A): A
  def mzero: A
}

object Monoid {
  implicit val IntMonoid: Monoid[Int] = new Monoid[Int] {
    def mappend(a: Int, b: Int) = a + b
    def mzero = 0
  }

yutaono

// compile error

import scala.annotation.tailrec

@tailrec
def fib(n: Int): Int = n match {
  case 1 | 2 => 1
  case _ => fib(n - 1) + fib(n - 2)
}

yutaono

f1 = 1
f2 = 2
sum = 0

loop {
  break if f2 > 4000000
  sum += f2 if f2 % 2 == 0
  f2 = f1 + f2
  f1 = f2 - f1
}

yutaono

require 'date'

t1 = DateTime.parse(ARGV[0]) 
t2 = DateTime.parse(ARGV[1])

seconds = ((t2 - t1) * 24 * 60 * 60).to_i
r = seconds.divmod(60)

puts "#{r[0]}min#{r[1]}sec"

yutaono

require 'redis'
require 'hiredis'
 
$redis = Redis.new(
  host: "127.0.0.1",
  port: 6379,
  timeout: 30.0,
  driver: :hiredis
)

yutaono

// project euler 28 
//
// The sum of the vertices can be expressed as follows. The w is width of the square.
// 
// sum = (w - 2)^2 + (w - 1) 
// + (w - 2)^2 + 2(w - 1)
// + (w - 2)^2 + 3(w - 1)
// + (w - 2)^2 + 4(w - 1)
// = 4w^2 - 6w + 6
//

yutaono

import scala.io.Source

val source = Source.fromFile("triangle.txt")
val triangle = collection.mutable.Map[Int, List[Int]]()
source.getLines foreach { line =>
  triangle += triangle.size -> line.split(" ").map(_.toInt).toList
}

def neighborsMaxList(list: List[Int]): List[Int] = list match {
    case l if l.length == 1 => Nil

yutaono

# coding: utf-8

import math

def eratosthenes(x):
    sieve = []
    prime = []
    for num in range(2, x):
        sieve.append(num)

yutaono

private int gcd(int m, int n) {
    int r = m % n;
    if (r == 0) {
        return n;
    }
    return gcd(n, r);
}

yutaono

(load (expand-file-name (concat (getenv "HOME") "/.emacs.d/common.el")))