Day6_2022

Day6_2022.cs

var file = @"c:\code\AoC\AoC2022\Day6\input.txt";

var message = File.ReadAllText(file).AsSpan();
var set = new HashSet<char>(4);

var part1 = FindUniqueSegment(message, 4);
var part2 = FindUniqueSegment(message, 14);

(part1 == 1760).Dump("Part 1");
(part2 == 2974).Dump("Part 2");

int FindUniqueSegment(ReadOnlySpan<char> message, int segmentLength)
{
	for (int i = 0; i < message.Length - segmentLength - 1; i++)
	{
		if (CheckForDuplicates(message.Slice(i, segmentLength), segmentLength))
		{
			return (i + segmentLength);
		}
	}
	
	return -1;
}

bool CheckForDuplicates(ReadOnlySpan<char> chars, int count)
{
	set.Clear();
	foreach(var c in chars)
		set.Add(c);
	
	return set.Count == count;
}