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搬移規則前，先對清正負數的取整分界

兩個明訂半數取整法真正跑一次，再核條件結果。

輸出移植及獨立再生成 →

下載完整個案資料及參考答案 ↓

訂判斷及所需輸入

本例先把分數取整，再查結果絕對值是否至少三。半數取偶把5/2 成二，條件否；半數遠離零成三，條件是。程序用整數分子、分母及 BigInt 商餘數，不是二進位小數相等問題。

已填本地測試工作表
情況輸入 JSON
原例測試{"numerator":5,"denominator":2,"policy":"ties-even","threshold":3}
下載可編輯 CSV ↓

跑所附比較

兩種算法由本例明訂。分子可正可負，但須為安全整數；分母須為正安全整數，門檻則是非負安全整數。整數零以0保留，不推真正規則引擎預設。

錯誤及所需輸出
路徑輸出 JSON
錯誤路徑{"rounded":3,"predicate":true}
所需路徑{"rounded":2,"predicate":false}
下載可編輯 CSV ↓
完整本地 Node24.14.1 程序
import assert from 'node:assert/strict';

const run=function run(i,corrected=true){
    if(!['ties-even','ties-away'].includes(i.policy)||!Number.isSafeInteger(i.numerator)||!Number.isSafeInteger(i.denominator)||i.denominator<1||!Number.isSafeInteger(i.threshold)||i.threshold<0)return {held:true};
    const signed=BigInt(i.numerator),n=signed<0n?-signed:signed,d=BigInt(i.denominator);let q=n/d;const r=n%d;
    const away=!corrected||i.policy==='ties-away';if(r*2n>d||(r*2n===d&&(away||q%2n===1n)))q++;
    const rounded=Number(signed<0n?-q:q);return {rounded,predicate:Math.abs(rounded)>=i.threshold};
  };
const cases=[{"input":{"numerator":5,"denominator":2,"policy":"ties-even","threshold":3},"corrected":false,"expected":{"rounded":3,"predicate":true}},{"input":{"numerator":5,"denominator":2,"policy":"ties-even","threshold":3},"corrected":true,"expected":{"rounded":2,"predicate":false}},{"input":{"numerator":-5,"denominator":2,"policy":"ties-even","threshold":3},"corrected":true,"expected":{"rounded":-2,"predicate":false}},{"input":{"numerator":-5,"denominator":2,"policy":"ties-away","threshold":3},"corrected":true,"expected":{"rounded":-3,"predicate":true}},{"input":{"numerator":51,"denominator":20,"policy":"ties-even","threshold":3},"corrected":true,"expected":{"rounded":3,"predicate":true}},{"input":{"numerator":-49,"denominator":20,"policy":"ties-even","threshold":3},"corrected":true,"expected":{"rounded":-2,"predicate":false}},{"input":{"numerator":5,"denominator":2,"policy":null,"threshold":3},"corrected":true,"expected":{"held":true}},{"input":{"numerator":5,"denominator":0,"policy":"ties-even","threshold":3},"corrected":true,"expected":{"held":true}}];
for(const test of cases){const actual=await run(test.input,test.corrected);assert.deepEqual(actual,test.expected);console.log(actual);}
下載可執行例子 ↓

按邊界依據作判斷

負−5/2 分出−2、−3；附近51/20、−49/20 試非半數。算法未知或分母零便停。

  1. 訂清半數取整法
  2. 跑正負分界
  3. 對最後條件判斷

引擎未訂算法，不能自行估預設。

可編輯邊界輸入及結果
條件輸入 JSON預期輸出 JSON
負數剛好半數{"numerator":-5,"denominator":2,"policy":"ties-even","threshold":3}{"rounded":-2,"predicate":false}
負半數明訂遠離零{"numerator":-5,"denominator":2,"policy":"ties-away","threshold":3}{"rounded":-3,"predicate":true}
正數剛超半數{"numerator":51,"denominator":20,"policy":"ties-even","threshold":3}{"rounded":3,"predicate":true}
負數幅度未到半數{"numerator":-49,"denominator":20,"policy":"ties-even","threshold":3}{"rounded":-2,"predicate":false}
取整算法未知{"numerator":5,"denominator":2,"policy":null,"threshold":3}{"held":true}
分母零不在規則內{"numerator":5,"denominator":0,"policy":"ties-even","threshold":3}{"held":true}
下載可編輯 CSV ↓

算式文字相同，原例條件就可直接搬嗎？

查看參考答案

不是。半數規則令二或三不同，條件也變否或是。使用前按已訂算法把正負兩邊重試。

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