diff --git a/aoc2021.test/DayTests.cs b/aoc2021.test/DayTests.cs
index 31b1170..c8427a6 100644
--- a/aoc2021.test/DayTests.cs
+++ b/aoc2021.test/DayTests.cs
@@ -8,6 +8,7 @@ public class DayTests
[DataRow(typeof(Day02), "2272262", "2134882034")]
[DataRow(typeof(Day03), "3009600", "6940518")]
[DataRow(typeof(Day04), "8580", "9576")]
+ [DataRow(typeof(Day05), "7318", "19939")]
public void CheckAllDays(Type dayType, string part1, string part2)
{
var s = Stopwatch.StartNew();
@@ -42,7 +43,7 @@ public class DayTests
[DataRow(typeof(Day02), "150", "900")]
[DataRow(typeof(Day03), "198", "230")]
[DataRow(typeof(Day04), "4512", "1924")]
- [DataRow(typeof(Day05), "5", "")]
+ [DataRow(typeof(Day05), "5", "12")]
public void CheckTestInputs(Type dayType, string part1, string part2)
{
Day.UseTestInput = true;
diff --git a/aoc2021/Day05.cs b/aoc2021/Day05.cs
index aa82eff..8653e08 100644
--- a/aoc2021/Day05.cs
+++ b/aoc2021/Day05.cs
@@ -1,82 +1,29 @@
-using System.Drawing;
-
-namespace aoc2021;
+namespace aoc2021;
///
/// Day 5:
///
public sealed class Day05 : Day
{
- private readonly List _lines;
-
public Day05() : base(5, "Hydrothermal Venture")
{
- _lines = Input.Select(l => new Line(l)).ToList();
}
- private class Line
- {
- public int X1 { get; }
- public int X2 { get; }
- public int Y1 { get; }
- public int Y2 { get; }
+ private int Solve(bool diagonals = false) =>
+ Input
+ .Where(s => !string.IsNullOrEmpty(s))
+ .Select(s => s.Split(" -> "))
+ .Select(a => a.Select(i => i.Split(',')).SelectMany(i => i.Select(int.Parse)).ToList())
+ .Where(t => diagonals || t[0] == t[2] || t[1] == t[3])
+ .SelectMany(t =>
+ Enumerable.Range(0, Math.Max(Math.Abs(t[0] - t[2]), Math.Abs(t[1] - t[3])) + 1)
+ .Select(i => (
+ t[0] > t[2] ? t[2] + i : t[0] < t[2] ? t[2] - i : t[2],
+ t[1] > t[3] ? t[3] + i : t[1] < t[3] ? t[3] - i : t[3])))
+ .GroupBy(k => k)
+ .Count(k => k.Count() > 1);
- public readonly List AllPoints = new();
-
- public Line(string line)
- {
- var s = line
- .Split(" -> ")
- .Select(i => i.Split(',').Select(int.Parse))
- .SelectMany(i => i)
- .ToList();
-
- X1 = s[0];
- X2 = s[1];
- Y1 = s[2];
- Y2 = s[3];
+ public override string Part1() => $"{Solve()}";
- if (X1 == X2)
- {
- var minY = Math.Min(Y1, Y2);
- var maxY = Math.Max(Y1, Y2);
-
- for (var i = 0; i < maxY - minY; i++)
- {
- AllPoints.Add(new(minY + i, X1));
- }
- }
- else if (Y1 == Y2)
- {
- var minX = Math.Min(X1, X2);
- var maxX = Math.Max(X1, X2);
-
- for (var i = 0; i < maxX - minX; i++)
- {
- AllPoints.Add(new(minX + i, Y1));
- }
- }
- else
- {
- var oX = X1 < X2 ? 1 : -1;
- var oY = Y1 < Y2 ? 1 : -1;
- for (var i = 0; i < Math.Abs(X1 - X2); i++)
- {
- AllPoints.Add(new(X1 + i * oX, Y1 + i * oY));
- }
- }
- }
- }
-
- public override string Part1()
- {
- var groups = _lines
- .Where(l => l.X1 != l.X2 && l.Y1 != l.Y2)
- .SelectMany(l => l.AllPoints)
- .GroupBy(x => x);
-
- return $"{groups.Count(g => g.Count() > 1)}";
- }
-
- public override string Part2() => "";
+ public override string Part2() => $"{Solve(diagonals: true)}";
}