harunorimurata

function gcd(m, n) { return n ? gcd(n, m % n) : m; }

harunorimurata

// CalcAgeAt calculates the age at the given time.
func CalcAgeAt(t time.Time, birthDay time.Time) int {
  age := t.Year() - birthDay.Year()
  if t.YearDay() < birthDay.YearDay() {
    age--
  }
  return age
}

harunorimurata

// Kahan-Babuska algorithm
export const sum = (x: number[]) => {
  if (x.length === 0) return 0
  let res = x[0], c = 0, t = 0
  for (let i = 1; i < x.length; i++) {
    t = res + x[i]
    if (Math.abs(res) >= Math.abs(x[i])) {
      c += res - t + x[i]
    } else {
      c += x[i] - t + res

harunorimurata

const grades = ['小1', '小2', '小3', '小4', '小5', '小6', '中1', '中2', '中3'];

// 誕生日からat時点での学年を算出
const birthdayToSchoolGrade = (birthday, at) => {
  const d = new Date(at);
  d.setMonth(d.getMonth() - 3);
  d.setMonth(3);
  d.setDate(1);
  const bd = new Date(birthday);
  const dNum = Number(d.toISOString().substring(0, 10).replaceAll('-', ''));

harunorimurata

const memoize = (func) => {
  const memo = new Map()
  return (...args) => {
    const key =  JSON.stringify(args)
    if (!memo.has(key)) memo.set(key, func(...args))
    return memo.get(key)
  }
}

/*

harunorimurata

#!/bin/bash

FROM_USER=user1
FROM_HOST=host1
FROM_DB=database1
FROM_TBL=table1

TO_USER=user2
TO_HOST=host2
TO_DB=database2

harunorimurata

func Repeat(s string, n uint) string {
	switch n {
	case 0:
		return ""
	case 1:
		return s
	}

	max := len(s) * int(n)
	var b strings.Builder

harunorimurata

function sharpeRatio(array, interest = 0) {
  if (array.length < 3) return { mean: 0, sd: 0, sharpeRatio: 0 };
  let mean = 0, sqsum = 0, l = array.length;
  for (let n = 1; n < l; n++) {
    const changeRate = (array[n] - array[n - 1]) / array[n - 1];
    const x = changeRate - mean;
    mean += x / n;
    sqsum += (n - 1) * x * x / n;
  }
  const sd = Math.sqrt(sqsum / (l - 1));

harunorimurata

// t期運用時点における運用総額をs(t)とする。
// 初期金額をα，各期の積立金額をβ，期待リターンをR(= 1 + r)とすると，各期の運用総額sは，期間tの関数S(t)として次の式で表される。
//
// S(t) = (α * R^t) + β * Σ(k = 0, t - 1) R^k
//
// ※各期の計算は以下のようになる
//
// S(t = 0)  =    α
// S(t = 1)  =    α * R + β                    =  (α * R^1) + (β * R^0)
// S(t = 2)  =   (α * R + β) * R + β           =  (α * R^2) + (β * R^1 + β * R^0)

harunorimurata

function debounce(fun, wait = 0) {
  let id = null;
  return () => {
    if (id !== null) clearTimeout(id)
    id = setTimeout(() => {
      fun();
      id = null;
    }, wait);
  };
}