codewars练习（javascript）-2021/3/5

codewars-js练习

2021/3/5

github 地址

my github地址，上面有做的习题记录，不断更新…

【1】<7kyu>【Convert an array of strings to array of numbers】

example：

["1", "2", "3"] //[1, 2, 3]
["1.1","2.2","3.3"]// [1.1,2.2,3.3]

solution

<script type="text/javascript">
        function toNumberArray(stringarray){
            // console.log(stringarray)
            var result = [];
            for(var i=0;i<stringarray.length;i++){
                if(stringarray[i]%1 ==0){
                    result.push(parseInt(stringarray[i]))
                }else{
                    result.push(parseFloat(stringarray[i]))
                }
            }
            return result
        }
        // 验证
        console.log(toNumberArray(["1.1","2.2","3.3"]));// [1.1,2.2,3.3]
        console.log(toNumberArray(['1','2','3']))
	</script>

【2】<7kyu>【Nth Root of a Number】

example：

Input: x=4, n=2, output: 2. The square root of 4 is 2, 2^2 = 4
Input: x=8, n=3, output: 2. The cube root of 8 is 2 , 2^3 = 8
Input: x=256, n=4, output: 4. The 4th root of 256 is 4 , 4^4 = 256
Input: x=9, n=2, output: 3. The square root of 9 is 3 , 3^2 = 9
Input: x=6.25, n=2, output: 2.5. The square root of 6.25 is 2.5 , 2.5^2 = 6.25

solution

<script type="text/javascript">
        function root(x,n) {
            // console.log(x,n)
            return Math.pow(x, 1/n)
        }
        // 验证
        console.log(root(4,2));//2
        console.log(root(256,4));//4
    </script>

【3】<6kyu>【Roman Numerals Decoder】

So 1990 is rendered "MCMXC" (1000 = M, 900 = CM, 90 = XC) and 2008 is rendered "MMVIII" (2000 = MM, 8 = VIII). The Roman numeral for 1666, "MDCLXVI", uses each letter in descending order.
Symbol    Value
I          1
V          5
X          10
L          50
C          100
D          500
M          1,000

example：

solution('XXI'); // should return 21

solution

<script type="text/javascript">
        
        function solution(roman){
            console.log(roman)
            var value = {'I':1,'V':5,'X':10,'L':50,'C':100,'D':500,'M':1000};
            var arr = roman.split('');
            var sum =0;
            for(var i=0;i<arr.length;i++){
                if (i>0 && value[arr[i]]>value[arr[i-1]]){
                    sum = sum - 2*value[arr[i-1]]
                }
                sum += value[arr[i]];
            }
            return sum
        } 
        // 验证
        // console.log(solution('XXI'));//21
        // console.log(solution('I'));//1
        console.log(solution('IV'));// 4
        // console.log(solution('MMVIII'));//2008
        // console.log(solution('MDCLXVI'));//1666
    </script>

以上为自己思路供大家参考，可能有更优的思路。