codewars练习（javascript）-2021/3/16

最新推荐文章于 2021-04-15 18:07:44 发布

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本文介绍了两道Codewars JavaScript练习题的解决方法。第一题为计算金字塔层级，通过给定球的数量来确定金字塔的层数。第二题为计算父亲年龄是儿子年龄两倍的时间点。文中给出了具体的实现代码及测试案例。

文章目录

- codewars-js练习
- - 2021/3/16

codewars-js练习

2021/3/16

github 地址

my github地址，上面有做的习题记录，不断更新…

【1】<7kyu>【Billiards pyramid】

example：

     *
   *   *
 *   *    *
       
pyramid(1) == 1

pyramid(3) == 2

pyramid(6) == 3

pyramid(10) == 4

pyramid(15) == 5

思路

假设 pyramid(balls) == n；则满足 $\frac{n^2+n}{2}= balls$ ，因此现在反求出n即可。

solution

<script type="text/javascript">
    function pyramid(balls) {
        // console.log(balls);
        var deta = 1 + 8*balls;
        var result = (-1+Math.sqrt(deta,2))/2;
        return Math.floor(result);
    }

    // 验证
    console.log(pyramid(21));//6
    console.log(pyramid(10));//4
</script>

【2】<8kyu>【Twice as old】

Your function takes two arguments:

current father’s age (years)
current age of his son (years)

Сalculate how many years ago the father was twice as old as his son (or in how many years he will be twice as old).

example：

(36,7)//22
(55,30)//5
(29,0)//29

solution

<script type="text/javascript">
    function twiceAsOld(dadYearsOld, sonYearsOld) {
        // console.log(dadYearsOld,sonYearsOld)
        return Math.abs(sonYearsOld * 2 - dadYearsOld)
    }

    // 验证
    console.log(twiceAsOld(36,7));// 22
    console.log(twiceAsOld(42,21));// 0
    console.log(twiceAsOld(29,0));// 29
    console.log(twiceAsOld(55,30));//5
</script>