tanishiking

object FibGen {

  def main(args: Array[String]): Unit = {
    fibGen.take(10).print
  }

  private[this] lazy val fibGen: Stream[Int] = 0 #:: 1 #:: fibGen.zip(fibGen.tail).map(n => n._1 + n._2)

}

tanishiking

scala> (1 to 10000000).filter(_ % 2 == 0).take(5)
// Range(1, 2, ...., 10000000) というコレクションを展開した上で
// 全てに対して filter などの処理がが行われるためメモリに大きな負担を与え
// 最終的に必要なのは前方5つだけなのに全体をなめるので処理にかなり時間がかかる.

scala> (1 to 10000000).view.filter(_ % 2 == 0).take(5).force
res0: scala.collection.immutable.IndexedSeq[Int] = Vector(5, 10, 15, 20, 25)
// filter や take は遅延評価される
// force メソッドで正格なコレクションに戻すことができる.

tanishiking

scala> 1 :: 2 :: 3 :: Nil
res22: List[Int] = List(1, 2, 3)

scala Stream.cons(1, Stream.cons(2, Stream.cons (3, Stream.empty)))
res23: Stream.Cons[Int] = Stream(1, ?)

scala> 1 #:: 2 #:: 3 #:: Stream.empty
res24: scala.collection.immutable.Stream[Int] = Stream(1, ?)

tanishiking

# -*- coding: utf-8 -*-

from time import sleep
import json
import pickle

import lxml.html

TARGET_URL = 'http://www.kyochari-navi.jp/churin/index.html'
BASE_URL = 'http://www.kyochari-navi.jp/churin/'

tanishiking

from sys import maxsize


class Alignmenter(object):
    def __init__(self, array1, array2):
        self.array1 = array1
        self.array2 = array2
        self.rows = len(self.array1) + 1
        self.cols = len(self.array2) + 1
        self.table = []

tanishiking

object LevenshteinDistance {
  private def editDistance(str1: String, str2: String): Int = {
    val cols: Int = str1.length
    val rows: Int = str2.length
    val chars1: Array[Char] = str1.toCharArray
    val chars2: Array[Char] = str2.toCharArray
    val dp = new Array[Array[Int]](rows + 1).map(ys => new Array[Int](cols + 1))

    for (row <- 0 to rows) {
      dp(row)(0) = row

tanishiking

object problem50 {
  def getMaxSumOfPrimes(limit: Int): Option[Int] = {
    // 1000000以下の素数の遅延リスト
    lazy val primes: Stream[Int] = Stream.cons(2, Stream.from(3).filter(i => primes.takeWhile(j => j * j <= i).forall(i % _ > 0))).takeWhile(_ <= limit)
    def isPrime(num: Int): Boolean = primes.contains(num)

    // 素数を小さい順に足していって1000000以下で最大となるまでの素数の遅延リスト
    val primeSumLimit: List[Int] = primes.takeWhile(i=> primes.takeWhile(_ <= i).map(_.toLong).sum <= limit).toList
    for (span <- primeSumLimit.length to 1 by -1) {
      if (primeSumLimit.sliding(span).map(_.sum).exists(isPrime)) {

tanishiking

class hoge:
    def __init__(self):
        self.a = 1
    def __get_a(self):
        return self.a
    def geta(self):
        # 普通に __get_a()にアクセスできる
        a = self.__get_a()
        return a

tanishiking

FROM ubuntu:14.04
RUN apt-get update
RUN apt-get install -y software-properties-common
RUN apt-key adv --recv-keys --keyserver hkp://keyserver.ubuntu.com:80 0x5a16e7281be7a449
RUN add-apt-repository "deb http://dl.hhvm.com/ubuntu $(lsb_release -sc) main"
RUN apt-get update
RUN apt-get install -y hhvm
RUN hhvm --version

tanishiking

import numpy as np
import matplotlib
from math import sqrt
matplotlib.use('TkAgg')
import matplotlib.pyplot as plt


def binomial_to_normal(samples, trials, probability, bins=50):
    data = []
    for i in range(samples):