<?xml version="1.0" encoding="utf-8"?><rss version="2.0" xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:sy="http://purl.org/rss/1.0/modules/syndication/"><channel><title>MagicLen</title><link>https://magiclen.org/category/math-logic/feed</link><description>多元化原創文章，內容包羅萬象，有程式語言、網站應用、軟體介紹、硬體介紹、作業系統、旅行遊記、專題採訪、益智問題、文學創作，以及作者們的知識分享和作品分享。</description><language>zh-TW</language><lastBuildDate>Sat, 18 Apr 2026 07:03:41 +0000</lastBuildDate><sy:updatePeriod>hourly</sy:updatePeriod><sy:updateFrequency>8</sy:updateFrequency><sy:updateBase>1970-01-01T00:00+00:00</sy:updateBase><item><title>寫程式算階乘，關於階乘的三兩事</title><link>https://magiclen.org/factorial</link><description><![CDATA[    <img src="https://magiclen.org/wp-content/uploads/2022/08/factorial-220x162.png" srcset="https://magiclen.org/wp-content/uploads/2022/08/factorial-220x162.png 1x, https://magiclen.org/wp-content/uploads/2022/08/factorial-440x324.png 2x, https://magiclen.org/wp-content/uploads/2022/08/factorial-660x486.png 3x" alt="">
正整數的階乘(Factorial)是小於或等於該數的所有正整數的乘積，若正整數為N，用N!來表示N的階乘。至於0!是階乘的特例，它被定義為1。階乘的運算具有遞迴(recursion)概念，常作為學習程式邏輯的材料，而這篇文章將會說明階乘相關的程式計算。]]></description><category>研究分享</category><category>Java</category><category>Rust</category><category>數學邏輯</category><category>Go</category><category>JavaScript</category><category>Java</category><category>JavaScript</category><category>Rust</category><category>TypeScript</category><category>階乘</category><category>Go</category><guid>https://magiclen.org/factorial</guid><pubDate>Thu, 27 Oct 2022 12:00:00 +0800</pubDate><dc:creator>Magic Len</dc:creator></item><item><title>如何寫程式來做等值的貨幣或是物品的數量換算？</title><link>https://magiclen.org/item-exchange</link><description><![CDATA[    <img src="https://magiclen.org/wp-content/uploads/2022/06/business-18107_1920-220x162.jpg" srcset="https://magiclen.org/wp-content/uploads/2022/06/business-18107_1920-220x162.jpg 1x, https://magiclen.org/wp-content/uploads/2022/06/business-18107_1920-440x324.jpg 2x, https://magiclen.org/wp-content/uploads/2022/06/business-18107_1920-660x486.jpg 3x" alt="">
不同國家有不同的貨幣流通，不同的貨幣也會有不同的價值。其實也不只貨幣，任何物品，無論實體的或是虛擬的都一樣，只要價值可以被衡量，就可以被等值換算。講到錢就傷感情，以蘋果和橘子來舉例好了，假設2顆蘋果等值於3粒橘子，那麼8顆蘋果就會等值於12粒橘子。]]></description><category>研究分享</category><category>Java</category><category>Rust</category><category>數學邏輯</category><category>JavaScript</category><category>Java</category><category>JavaScript</category><category>Rust</category><category>TypeScript</category><guid>https://magiclen.org/item-exchange</guid><pubDate>Thu, 28 Jul 2022 12:00:00 +0800</pubDate><dc:creator>Magic Len</dc:creator></item><item><title>認識數字系統，進行任意進制的超長整數運算(加、減、乘、除)</title><link>https://magiclen.org/numeral-system-big-integer</link><description><![CDATA[    <img src="https://magiclen.org/wp-content/uploads/2020/05/big-number-220x162.jpg" srcset="https://magiclen.org/wp-content/uploads/2020/05/big-number-220x162.jpg 1x, https://magiclen.org/wp-content/uploads/2020/05/big-number-440x324.jpg 2x, https://magiclen.org/wp-content/uploads/2020/05/big-number-660x486.jpg 3x" alt="">
電腦程式在進行整數數值計算的時候，會受到變數型別的記憶體空間使用大小而有數值表示範圍的限制，所以當遇到過長的數值時，就無法正常地運算出結果。]]></description><category>研究分享</category><category>Java</category><category>Rust</category><category>數學邏輯</category><category>Go</category><category>JavaScript</category><category>Java</category><category>JavaScript</category><category>Rust</category><category>大數運算</category><category>TypeScript</category><category>Go</category><guid>https://magiclen.org/numeral-system-big-integer</guid><pubDate>Tue, 14 Jul 2020 12:00:42 +0800</pubDate><dc:creator>Magic Len</dc:creator></item><item><title>如何用程式進行質因數分解和尋找最大公因數與最小公倍數？</title><link>https://magiclen.org/prime-factorization-gcd-lcm</link><description><![CDATA[    <img src="https://magiclen.org/wp-content/uploads/2018/10/pay-819587_1920-220x162.jpg" srcset="https://magiclen.org/wp-content/uploads/2018/10/pay-819587_1920-220x162.jpg 1x, https://magiclen.org/wp-content/uploads/2018/10/pay-819587_1920-440x324.jpg 2x, https://magiclen.org/wp-content/uploads/2018/10/pay-819587_1920-660x486.jpg 3x" alt="">
若正整數a除以正整數b可以整除，則稱b為a的因數(Factor)，a為b的倍數(Multiple)，1是所有正整數最小的因數，任意正整數最大的因數就是該正整數本身。若a同時是x和y的因數，則稱a是x和y的公因數(Common Divisor)，如果a是x和y的公因數中最大的一個，則稱a是x和y的最大公因數(Greatest Common Divisor，簡稱GCD)。若a同時是x和y的倍數，則稱a...]]></description><category>研究分享</category><category>Java</category><category>Rust</category><category>數學邏輯</category><category>演算法</category><category>Go</category><category>JavaScript</category><category>Java</category><category>JavaScript</category><category>Rust</category><category>TypeScript</category><category>質因數分解</category><category>最大公因數</category><category>最小公倍數</category><category>輾轉相除法</category><category>Go</category><guid>https://magiclen.org/prime-factorization-gcd-lcm</guid><pubDate>Thu, 9 Jul 2020 12:00:35 +0800</pubDate><dc:creator>Magic Len</dc:creator></item><item><title>如何寫程式來找出河內塔的最佳解？那不寫程式的話呢？</title><link>https://magiclen.org/tower-of-hanoi</link><description><![CDATA[    <img src="https://magiclen.org/wp-content/uploads/2020/04/Untitled-220x162.jpg" srcset="https://magiclen.org/wp-content/uploads/2020/04/Untitled-220x162.jpg 1x, https://magiclen.org/wp-content/uploads/2020/04/Untitled-440x324.jpg 2x, https://magiclen.org/wp-content/uploads/2020/04/Untitled-660x486.jpg 3x" alt="">
河內塔(Tower of Hanoi)是一個很謎的數學遊戲，它是由三根桿子(Rod)和一個以上大小不同的碟片(Disk)所組成的。在遊戲的一開始，這些碟片按照底大頂小的順序疊在一起，由三根桿子中的其中一根串著。玩家每次可以移動一個碟片到其它的桿子上，但是不能將比較大的碟片疊在比較小的碟片上。當玩家把所有碟片都串到指定的桿子，遊戲就結束了。]]></description><category>研究分享</category><category>Java</category><category>Rust</category><category>數學邏輯</category><category>Go</category><category>JavaScript</category><category>Java</category><category>JavaScript</category><category>Rust</category><category>TypeScript</category><category>河內塔</category><category>Go</category><guid>https://magiclen.org/tower-of-hanoi</guid><pubDate>Thu, 25 Jun 2020 20:00:28 +0800</pubDate><dc:creator>Magic Len</dc:creator></item><item><title>人死後會上天堂還是地獄？用數學算給你看</title><link>https://magiclen.org/heaven-or-hell</link><description><![CDATA[    <img src="https://magiclen.org/wp-content/uploads/2018/11/hell-735995_1920-220x162.jpg" srcset="https://magiclen.org/wp-content/uploads/2018/11/hell-735995_1920-220x162.jpg 1x, https://magiclen.org/wp-content/uploads/2018/11/hell-735995_1920-440x324.jpg 2x, https://magiclen.org/wp-content/uploads/2018/11/hell-735995_1920-660x486.jpg 3x" alt="">
在許多宗教信仰中有關於天堂和地獄的描述，簡單來說，天堂是一個只有快樂沒有痛苦的地方，人在生前如果做了很多好事，死後就可以「升天」到天堂享受；而人在生前如果做了很多壞事，死後就會「掉落」到地獄受苦。宗教藉由描述一個做好事就會產生好結果，做壞事就會產生壞結果的道理，來引導人們多做好事，少做壞事。假設天堂和地獄真的存在，人死後又是怎麼去的呢？我們應該都沒見過哪個人死後遺體就突然消失，跑去天堂或是地獄吧？...]]></description><category>數學邏輯</category><category>宗教</category><category>天堂</category><category>地獄</category><category>靈魂</category><guid>https://magiclen.org/heaven-or-hell</guid><pubDate>Fri, 21 Dec 2018 12:00:40 +0800</pubDate><dc:creator>Magic Len</dc:creator></item><item><title>馬鈴薯到底有多重？馬鈴薯悖論</title><link>https://magiclen.org/potato-paradox</link><description><![CDATA[    <img src="https://magiclen.org/wp-content/uploads/2018/09/PIXNIO-342298-1920x1280-220x162.jpg" srcset="https://magiclen.org/wp-content/uploads/2018/09/PIXNIO-342298-1920x1280-220x162.jpg 1x, https://magiclen.org/wp-content/uploads/2018/09/PIXNIO-342298-1920x1280-440x324.jpg 2x, https://magiclen.org/wp-content/uploads/2018/09/PIXNIO-342298-1920x1280-660x486.jpg 3x" alt="">
馬鈴薯是一種含水量非常高的塊莖，若有一籮筐的馬鈴薯總重100公斤，而這些馬鈴薯共含有99%的水份，晚上將它們拿到外頭陰乾，到隔天早上馬鈴薯所含的水份變為98%，此時它們的總重量只剩50公斤。咦？好像哪裡怪怪的？水份只減少1%，馬鈴薯的重量怎麼只剩一半了呢？]]></description><category>數學邏輯</category><category>悖論</category><category>謬論</category><guid>https://magiclen.org/potato-paradox</guid><pubDate>Wed, 24 Oct 2018 12:00:37 +0800</pubDate><dc:creator>Magic Len</dc:creator></item><item><title>一片雪花的周長比地球直徑還要長，面積卻比一枚硬幣還要小！？</title><link>https://magiclen.org/snowflake</link><description><![CDATA[    <img src="https://magiclen.org/wp-content/uploads/2018/09/pexels-photo-853132-220x162.jpg" srcset="https://magiclen.org/wp-content/uploads/2018/09/pexels-photo-853132-220x162.jpg 1x, https://magiclen.org/wp-content/uploads/2018/09/pexels-photo-853132-440x324.jpg 2x, https://magiclen.org/wp-content/uploads/2018/09/pexels-photo-853132-660x486.jpg 3x" alt="">
雪花是空中的水蒸氣凝華而成的，當空氣的溫度降低，水蒸氣變為超過飽和時，就會在以塵埃等物質作為結晶核，開始結晶，然後逐步長大形成雪花。單片雪花的大小通常在0.05至4.6毫米之間，重量則只有0.2~0.5克。如果我們想要計算雪花的周長和面積，該怎麼計算呢？]]></description><category>數學邏輯</category><category>碎形</category><category>科赫曲線</category><guid>https://magiclen.org/snowflake</guid><pubDate>Tue, 16 Oct 2018 12:00:11 +0800</pubDate><dc:creator>Magic Len</dc:creator></item><item><title>如何有效率地寫程式判斷質數和尋找質數？</title><link>https://magiclen.org/prime-number</link><description><![CDATA[    <img src="https://magiclen.org/wp-content/uploads/2018/10/pay-819587_1920-220x162.jpg" srcset="https://magiclen.org/wp-content/uploads/2018/10/pay-819587_1920-220x162.jpg 1x, https://magiclen.org/wp-content/uploads/2018/10/pay-819587_1920-440x324.jpg 2x, https://magiclen.org/wp-content/uploads/2018/10/pay-819587_1920-660x486.jpg 3x" alt="">
一個質數(Prime)是一個大於1，且無法找到除了自己本身和1之外的自然數能整除它的自然數。舉例來說，2、3、5、7、11、13和17均為質數。質數是數學上的難題，即便數學已經過幾千年的發展，卻也還是無法找出一個能完美產生出質數的函數。在學習寫程式的過程中，儘管在現實社會中幾乎用不到，我們還是會常常遇到判斷質數或是尋找質數的問題。那麼，究竟要如何利用程式來處理判斷質數和尋找質數呢？]]></description><category>研究分享</category><category>Java</category><category>Rust</category><category>數學邏輯</category><category>Go</category><category>JavaScript</category><category>Java</category><category>JavaScript</category><category>質數</category><category>Rust</category><category>埃拉托斯特尼篩法</category><category>TypeScript</category><category>Go</category><guid>https://magiclen.org/prime-number</guid><pubDate>Sun, 14 Oct 2018 12:00:39 +0800</pubDate><dc:creator>Magic Len</dc:creator></item><item><title>射出去的箭是不動的？飛矢不動悖論</title><link>https://magiclen.org/arrow-paradox</link><description><![CDATA[    <img src="https://magiclen.org/wp-content/uploads/2018/09/arrow-220x162.png" srcset="https://magiclen.org/wp-content/uploads/2018/09/arrow-220x162.png 1x, https://magiclen.org/wp-content/uploads/2018/09/arrow-440x324.png 2x, https://magiclen.org/wp-content/uploads/2018/09/arrow-660x486.png 3x" alt="">
萬物的存在是靜止、不變且永恆的，變化與運動都只是幻覺，只是眼睛業障重罷了。試想一下，一支飛行的箭，它在飛行過程中的任何瞬間都有一個暫時的位置對吧？如果這個瞬間不動，下個瞬間不動，那麼這支箭是不是根本不會動？]]></description><category>數學邏輯</category><category>悖論</category><category>芝諾悖論</category><category>謬論</category><guid>https://magiclen.org/arrow-paradox</guid><pubDate>Wed, 10 Oct 2018 12:00:06 +0800</pubDate><dc:creator>Magic Len</dc:creator></item></channel></rss>