Linq Challenge (https://markheath.net/post/linq-challenge-3)

LinqChallengeQuestion1.cs

"1,2,1,1,0,3,1,0,0,2,4,1,0,0,0,0,2,1,0,3,1,0,0,0,6,1,3,0,0,0"
	.Split(',')
	.Select(x => Convert.ToInt32(x))
	.Segment((cur, prev, idx) => cur != prev)
	.Where(x => x.First() == 0)
	.Select(x => x.Count())
	.Max()

LinqChallengeQuestion2.cs

"4♣ 5♦ 6♦ 7♠ 10♥;10♣ Q♥ 10♠ Q♠ 10♦;6♣ 6♥ 6♠ A♠ 6♦;2♣ 3♥ 3♠ 2♠ 2♦;2♣ 3♣ 4♣ 5♠ 6♠"
	.Split(';')
	.Select(x => x
		.Split(' ')
		.GroupBy(
			y => y[0],
			(k, y) => new { Number = k, Count = y.Count(), })
		.OrderBy(y => y.Count)
		.ToList())
	.Where(x =>
		x.Count == 2 &&
		x[0].Count == 2 &&
		x[1].Count == 3)
	

LinqChallengeQuestion3.cs

Enumerable.Range(DateTime.Today.Year, 10)
	.Select(y => new DateTime(y, 12, 25))
	.Select(y => y.DayOfWeek)

LinqChallengeQuestion4.cs

"parts,traps,arts,rats,starts,tarts,rat,art,tar,tars,stars,stray"
	.Split(',')
	.Where(x => x.Length == 4)
	.Select(x => new { x, arr = x.OrderBy(c => c).ToArray(), })
	.Where(x => x.arr[0] == 'a' && x.arr[1] == 'r' && x.arr[2] == 's' && x.arr[3] == 't')
	.Select(x => x.x)

LinqChallengeQuestion5.cs

"Santi Cazorla, Per Mertesacker, Alan Smith, Thierry Henry, Alex Song, Paul Merson, Alexis Sánchez, Robert Pires, Dennis Bergkamp, Sol Campbell"
	.Split(',')
	.Select(x => x.Trim())
	.Select(x => new
	{
		x,
		Initials = x
			.Split(new[] { ' ' }, StringSplitOptions.RemoveEmptyEntries)
			.Select(y => y[0])
			.ToArray(),
	})
	.GroupBy(x => (x.Initials[0], x.Initials[1]))
	.Where(x => x.Count() > 1)
	.SelectMany(x => x)
	.Select(x => x.x)	

LinqChallengeQuestion6.cs

Enumerable.Range(0, (int)TimeSpan.FromHours(2).TotalSeconds + 1)
	.Except(
		"0:00:00-0:00:05;0:55:12-1:05:02;1:37:47-1:37:51"
			.Split(';')
			.Select(x => x.Split('-')
				.Select(y => TimeSpan.Parse(y))
				.Select(y => (int)y.TotalSeconds)
				.ToArray())
			// +1 here if exclusion times are closed sets (generally true); Can remove to match answer on website.
			.SelectMany(x => Enumerable.Range(x[0], x[1] - x[0] + 1)))
	.Segment((cur, prev, idx) => cur != prev + 1)
	.Select(x => new[] { TimeSpan.FromSeconds(x.First()), TimeSpan.FromSeconds(x.Last()), })
	.Select(x => $"{x[0]}-{x[1]}")