254 shades of grey

254 shades of grey

Description:

Why would we want to stop to only 50 shades of grey? Let‘s see to how many we can go.

Write a function that takes a number n as a parameter and return an array containing n shades of grey in hexadecimal code (#aaaaaa for example). The array should be sorted in ascending order starting with #010101, #020202, etc. (using lower case letters).

using System;

public static class shadesOfGrey(int n) {
  // returns n shades of grey in an array
}

As a reminder, the grey color is composed by the same number of red, green and blue: #010101, #aeaeae, #555555, etc. Also, #000000 and #ffffff are not accepted values.

When n is negative, just return an empty array. If n is higher than 254, just return an array of 254 elements.

Have fun

using System;
using System.Collections.Generic;
using System.Linq;

 public class Kata
    {
        public static string[] ShadesOfGrey(int n)
        {
            // returns n shades of grey in an array
            string[] array = null;
            if (n <= 0)
            {
                array = new string[] { };

            }
            else
            {
                if (n > 254)
                {
                    n = 254;
                }
                List<string> list = new List<string>();
                string str = string.Empty;
                for (int i = 1; i <= n; i++)
                {
                    str = i.ToString("x2");
                    str = "#" + string.Join(string.Empty, Enumerable.Repeat(str, 3));
                    list.Add(str);
                }
                array = list.ToArray();
            }
            return array;
        }
    }

其他人的写法

using System;

public class Kata{
public static string[] ShadesOfGrey(int n){
  string[] arr = null;
         n = n <= 0 ? 0 : (n > 254 ? 254 : n);
         if (n > 0)
         {
             arr = new string[n];
             for (int i = 1; i <= n; ++i)
             {
                 arr[i-1] = string.Format("#{0:x2}{1:x2}{2:x2}", i, i, i);
             }
         }
         return arr;
}
}

下面这个还需要学习

Math.Min以及Math.Max的使用

以及Linq的使用，select之后可以直接转换为Array

using System;
using System.Linq;

public static class Kata {
  public static string[] ShadesOfGrey(int count) {
    if (count < 0)
      count = 0;

    return Enumerable
      .Range(1, Math.Min(count, 254))
      .Select(x => string.Format("#{0:x2}{0:x2}{0:x2}", x))
      .ToArray();
  }
}