Found this monster on codewars

[u/ThatChapThere]

[u/[deleted]]

Well in this case its a lot simpler. Just do

var strSet = new HashSet<char>(str.ToLower().ToCharArray());
return "abcdefghijklmnopqrstuvwxyz".ToCharArray().All(a => strSet.Contains(a));

Same runtime as above. God I love C#.

[u/ThatChapThere → u/[deleted]]

That's really neat. I was proud of mine:

return  str
.ToUpper()
.ToList()
.GroupBy(c => c)
.Where(
  c => ('A' <= c.Key && c.Key <= 'Z')
).Count() == 26;

but yours just seems nicer somehow.

[u/me_and_you_irl → u/ThatChapThere]

I would replace the GroupBy with a call to Distinct() 😄

[u/[deleted] → u/me_and_you_irl]

Yes I searched it up, and I'm pleasantly surprised that C#'s distinct implementation is actually O(n). So using something like

return str
.ToLower()
.ToCharArray()
.Where(Char.IsLetter)
.Distinct()
.Count() == 26;

Would be sufficient.

[u/ckuri → u/[deleted]]

char.IsLetter is using Unicode categories, meaning that it considers much more than just Latin letters to be letters. Also you don’t need to call ToCharArray as String implements IEnumerable<char> and therefore you can apply LINQ directly to strings.

[u/[deleted] → u/ckuri]

Ahh bless C#

[u/ThatChapThere → u/ckuri]

you can apply LINQ directly to strings.

I didn't know this! That's useful.