2017-12-07_10-45-22.cs

int Part1(string[] passphrases) => passphrases.Where(IsValidPart1).Count();

int Part2(string[] passphrases) => passphrases.Where(IsValidPart2).Count();

bool IsValidPart1(string str) => IsValid(str, x => x);

bool IsValidPart2(string str) => IsValid(str, Alphabetize);

bool IsValid(string str, Func<string, string> projection)
{
	var segs = str.Split(' ').Select(projection).ToArray();
	
	return segs.Length > 1 && segs.SequenceEqual(segs.Distinct());
}

string Alphabetize(string str) => string.Concat(str.ToCharArray().OrderBy(c => c));