2019年 9月 の投稿一覧

• 2019.09.27

Javaのポリモフィズム動物園にインタフェースを導入した

import java.util.*; public class Main { public static void main(String[] args) throws Exception { Animal a; a = new Cat(3); a.say(); a = new Mike(5); a.say(); } } interface Sayable { void say(); } abstract class Animal implements Sayable { protected int age; public Animal(int age) { this.age = age; } public int getAge() { return this.age; } } class Cat extends Animal { public Cat(int age) { super(age); } public void say() { System.out.println("ニャー(" + this.age + ")"); } } class Mike extends Cat { public Mike(int age) { super(age); } public void say() { System.out.println("ミケニャー(" + this.age + ")"); } }

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import java.util.*;   public class Main {     public static void main(String[] args) throws Exception {         Animal a;           a = new Cat(3);         a.say();                  a = new Mike(5);         a.say();     } }   interface Sayable {     void say(); }   abstract class Animal implements Sayable {     protected int age;     public Animal(int age) {         this.age = age;     }     public int getAge() {         return this.age;     } }   class Cat extends Animal {     public Cat(int age) {         super(age);     }     public void say() {         System.out.println("ニャー(" + this.age + ")");     } }   class Mike extends Cat {     public Mike(int age) {         super(age);     }     public void say() {         System.out.println("ミケニャー(" + this.age + ")");     } }

ニャー(3) ミケニャー(5)

1 2	ニャー(3) ミケニャー(5)

• 2019.09.25

JavaScriptでquicksort

const main = () => { const p = console.log const getRandomInt = (min = 0, max = 9) => { const randomOffset = Math.floor(Math.random() * (max - min + 1)) return min + randomOffset } const dispArrayList = a => { a.forEach((v, k) => { p(k + " => " + v) }) } const getBlankArray = (len = 10) => { const a = [] for (let i = 0; i < len; i++) { a[i] = 0 } return a } const setRandomIntForArray = (a, min = 0, max = 9) => { const len = a.length for (let i = 0; i < len; i++) { a[i] = getRandomInt(min, max) } } const getPivot = (a, b, c) => { if (a < b) { if (b < c) { return b } else { return a < c ? c : a } } else { if (a < c) { return a } else { return b < c ? c : b } } } const swap = (a, l, r) => { const t = a[l] a[l] = a[r] a[r] = t } const quicksort = (a, left = 0, right = -1) => { if (right === -1) { right = a.length - 1 } if (right <= left) { return } let l = left let r = right const p = getPivot(a[l], a[l + 1], a[r]) while (true) { while (a[l] < p) { l++ } while (p < a[r]) { r-- } if (r <= l) { break; } swap(a, l, r) l++ r-- } quicksort(a, left, l - 1) quicksort(a, r + 1, right) } const sub = () => { const a = getBlankArray(30) setRandomIntForArray(a) p("ソート前", a) quicksort(a) p("ソート後", a) } sub() } main()

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const main = () => {   const p = console.log   const getRandomInt = (min = 0, max = 9) => {     const randomOffset = Math.floor(Math.random() * (max - min + 1))     return min + randomOffset   }   const dispArrayList = a => {     a.forEach((v, k) => {       p(k + " => " + v)     })   }   const getBlankArray = (len = 10) => {     const a = []     for (let i = 0; i < len; i++) {       a[i] = 0     }     return a   }   const setRandomIntForArray = (a, min = 0, max = 9) => {     const len = a.length     for (let i = 0; i < len; i++) {       a[i] = getRandomInt(min, max)     }   }   const getPivot = (a, b, c) => {     if (a < b) {       if (b < c) {         return b       } else {         return a < c ? c : a       }     } else {       if (a < c) {         return a       } else {         return b < c ? c : b       }     }   }   const swap = (a, l, r) => {     const t = a[l]     a[l] = a[r]     a[r] = t   }   const quicksort = (a, left = 0, right = -1) => {     if (right === -1) {       right = a.length - 1     }     if (right <= left) {       return     }     let l = left     let r = right     const p = getPivot(a[l], a[l + 1], a[r])     while (true) {       while (a[l] < p) {         l++       }       while (p < a[r]) {         r--       }       if (r <= l) {         break;       }       swap(a, l, r)       l++       r--     }     quicksort(a, left, l - 1)     quicksort(a, r + 1, right)   }   const sub = () => {     const a = getBlankArray(30)     setRandomIntForArray(a)     p("ソート前", a)     quicksort(a)     p("ソート後", a)   }   sub() } main()

ソート前 [ 8, 2, 7, 5, 4, 8, 0, 1, 6, 7, 7, 3, 8, 0, 7, 9, 5, 0, 4, 4, 1, 1, 3, 5, 1, 8, 9, 1, 0, 8 ] ソート後 [ 0, 0, 0, 0, 1, 1, 1, 1, 1, 2, 3, 3, 4, 4, 4, 5, 5, 5, 6, 7, 7, 7, 7, 8, 8, 8, 8, 8, 9, 9 ]

1 2	ソート前 [ 8, 2, 7, 5, 4, 8, 0, 1, 6, 7, 7, 3, 8, 0, 7, 9, 5, 0, 4, 4, 1, 1, 3, 5, 1, 8, 9, 1, 0, 8 ] ソート後 [ 0, 0, 0, 0, 1, 1, 1, 1, 1, 2, 3, 3, 4, 4, 4, 5, 5, 5, 6, 7, 7, 7, 7, 8, 8, 8, 8, 8, 9, 9 ]

• 2019.09.08

時間の昇順で指定したディレクトリのファイルパス一覧を取得する

const fs = require('fs') const getFilePathListSortedByTimeStampAsc = dir => { const fileList = [] files = fs.readdirSync(dir) for (const file of files) { const filePath = dir + '/' + file const mtime = fs.statSync(filePath).mtime fileList.push({ filePath: filePath, mtime: mtime }) } return fileList .sort((a, b) => a.mtime - b.mtime) // ASC .map(file => file.filePath) }

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const fs = require('fs')   const getFilePathListSortedByTimeStampAsc = dir => {   const fileList = []   files = fs.readdirSync(dir)   for (const file of files) {     const filePath = dir + '/' + file     const mtime = fs.statSync(filePath).mtime     fileList.push({       filePath: filePath,       mtime: mtime     })   }   return fileList     .sort((a, b) => a.mtime - b.mtime) // ASC     .map(file => file.filePath) }

• 2019.09.04

TypeScriptでフィボナッチ数列

const main = () => { const p: Function = console.log; const fibonacci: Function = (n: number): number => { switch (n) { case 0: return 0; case 1: return 1; default: return fibonacci(n - 1) + fibonacci(n - 2); } }; const sub = () => { const f: Function = fibonacci; const max: number = 20; for (let i: number = 0; i <= max; i++) { p("f(" + i + ") = " + f(i)); } }; sub(); }; main();

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const main = () => {   const p: Function = console.log;   const fibonacci: Function = (n: number): number => {     switch (n) {       case 0:         return 0;       case 1:         return 1;       default:         return fibonacci(n - 1) + fibonacci(n - 2);     }   };   const sub = () => {     const f: Function = fibonacci;     const max: number = 20;     for (let i: number = 0; i <= max; i++) {       p("f(" + i + ") = " + f(i));     }   };   sub(); }; main();

f(0) = 0 f(1) = 1 f(2) = 1 f(3) = 2 f(4) = 3 f(5) = 5 f(6) = 8 f(7) = 13 f(8) = 21 f(9) = 34 f(10) = 55 f(11) = 89 f(12) = 144 f(13) = 233 f(14) = 377 f(15) = 610 f(16) = 987 f(17) = 1597 f(18) = 2584 f(19) = 4181 f(20) = 6765

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f(0) = 0 f(1) = 1 f(2) = 1 f(3) = 2 f(4) = 3 f(5) = 5 f(6) = 8 f(7) = 13 f(8) = 21 f(9) = 34 f(10) = 55 f(11) = 89 f(12) = 144 f(13) = 233 f(14) = 377 f(15) = 610 f(16) = 987 f(17) = 1597 f(18) = 2584 f(19) = 4181 f(20) = 6765