2.1 KiB
| id | title | challengeType | videoUrl |
|---|---|---|---|
| 59c3ec9f15068017c96eb8a3 | Farey序列 | 5 |
--description--
编写一个返回n阶Farey序列的函数。该函数应该有一个参数n。它应该将序列作为数组返回。阅读以下内容了解更多详情：
阶数n的Farey序列 F n是在0和1之间的完全减少的分数的序列，当在最低阶段时，具有小于或等于n的分母，按照增大的大小排列。
Farey序列有时被错误地称为Farey系列。
每个Farey序列：
:: *以值0开头，由分数$ \ frac {0} {1} $表示
:: *以值1结尾，由$ \ frac {1} {1} $分数表示。
订单1到5的Farey序列是：
$ {\ bf \ it {F}} _ 1 = \ frac {0} {1}，\ frac {1} {1} $
$ {\ bf \ it {F}} _ 2 = \ frac {0} {1}，\ frac {1} {2}，\ frac {1} {1} $
$ {\ bf \ it {F}} _ 3 = \ frac {0} {1}，\ frac {1} {3}，\ frac {1} {2}，\ frac {2} {3}，\ frac {1} {1} $
$ {\ bf \ it {F}} _ 4 = \ frac {0} {1}，\ frac {1} {4}，\ frac {1} {3}，\ frac {1} {2}，\ frac {2} {3}，\ frac {3} {4}，\ frac {1} {1} $
$ {\ bf \ it {F}} _ 5 = \ frac {0} {1}，\ frac {1} {5}，\ frac {1} {4}，\ frac {1} {3}，\ frac {2} {5}，\ frac {1} {2}，\ frac {3} {5}，\ frac {2} {3}，\ frac {3} {4}，\ frac {4} {5 }，\ frac {1} {1} $
--hints--
farey是一种功能。
assert(typeof farey === 'function');
farey(3)应该返回一个数组
assert(Array.isArray(farey(3)));
farey(3)应该返回["1/3","1/2","2/3"]
assert.deepEqual(farey(3), ['1/3', '1/2', '2/3']);
farey(4)应该返回["1/4","1/3","1/2","2/4","2/3","3/4"]
assert.deepEqual(farey(4), ['1/4', '1/3', '1/2', '2/4', '2/3', '3/4']);
farey(5)应返回["1/5","1/4","1/3","2/5","1/2","2/4","3/5","2/3","3/4","4/5"]
assert.deepEqual(farey(5), [
'1/5',
'1/4',
'1/3',
'2/5',
'1/2',
'2/4',
'3/5',
'2/3',
'3/4',
'4/5'
]);