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tomislavpettomislavpet
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day 15
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3 files changed

+153
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‎day15/Program.cs

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using System.Numerics;
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class Sensor
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{
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public int X { get; set; }
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public int Y { get; set; }
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public int BeaconX { get; set; }
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public int BeaconY { get; set; }
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public int DeltaX { get; set; }
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public Sensor(int x, int y, int beaconX, int beaconY)
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{
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X = x;
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Y = y;
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BeaconX = beaconX;
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BeaconY = beaconY;
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DeltaX = Math.Abs(x - beaconX) + Math.Abs(y - beaconY);
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}
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public int MinXAtY(int y) => X - DeltaX + Math.Abs(Y - y);
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public int MaxXAtY(int y) => X + DeltaX - Math.Abs(Y - y);
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}
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class Program
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{
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static List<Sensor> sensors = new List<Sensor>();
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static void Solve1(int row)
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{
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var minX = sensors.Min(s => s.X - s.DeltaX);
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var maxX = sensors.Max(s => s.X + s.DeltaX);
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var score = 0;
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for (int i = minX; i <= maxX; i++)
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{
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var isBeacon = false;
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foreach (var s in sensors)
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{
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if (s.BeaconX == i && s.BeaconY == row)
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{
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isBeacon = true;
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break;
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}
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}
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if (isBeacon)
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continue;
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foreach (var s in sensors)
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{
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if (i >= s.MinXAtY(row) && i <= s.MaxXAtY(row))
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{
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score++;
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break;
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}
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}
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}
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Console.WriteLine(score);
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}
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static void Solve2(int maxBound)
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{
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for (var y = 0; y <= maxBound; y++)
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{
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var bounds = sensors.Select(s => new int[] {Math.Max(s.MinXAtY(y), 0), Math.Min(s.MaxXAtY(y), maxBound)})
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.Where(e => e[0] <= e[1]).ToList();
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bounds.Sort((a, b) => a[0].CompareTo(b[0]));
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var isMerged = true;
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while (isMerged && bounds.Count > 1)
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{
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isMerged = false;
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if (bounds[0][0] <= bounds[1][0] && bounds[0][1] >= bounds[1][0])
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{
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bounds[0][1] = Math.Max(bounds[0][1], bounds[1][1]);
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bounds.RemoveAt(1);
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isMerged = true;
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}
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}
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if (!isMerged || bounds[0][0] != 0 || bounds[0][1] != maxBound)
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{
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Console.WriteLine(((BigInteger) (bounds[0][1] + 1)) * 4000000 + y);
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break;
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}
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}
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}
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static void Main()
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{
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File.ReadAllLines("/Users/tpetrovic/Projects/aoc2022/day15/input.txt").ToList().ForEach(line =>
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{
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var parts = line.Replace("Sensor at x=", "").Replace(", y=", ",").Replace(": closest beacon is at x=", ",")
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.Replace(", y=", ",").Split(",");
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sensors.Add(new Sensor(int.Parse(parts[0]), int.Parse(parts[1]), int.Parse(parts[2]), int.Parse(parts[3])));
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});
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Solve1(2000000);
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Solve2(4000000);
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}
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}

‎day15/day15.csproj

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<Project Sdk="Microsoft.NET.Sdk">
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<PropertyGroup>
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<OutputType>Exe</OutputType>
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<TargetFramework>net6.0</TargetFramework>
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<ImplicitUsings>enable</ImplicitUsings>
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<Nullable>enable</Nullable>
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</PropertyGroup>
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</Project>

‎day15/input.txt

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Sensor at x=1555825, y=18926: closest beacon is at x=1498426, y=-85030
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Sensor at x=697941, y=3552290: closest beacon is at x=595451, y=3788543
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Sensor at x=3997971, y=2461001: closest beacon is at x=3951198, y=2418718
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Sensor at x=3818312, y=282332: closest beacon is at x=4823751, y=1061753
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Sensor at x=2874142, y=3053631: closest beacon is at x=3074353, y=3516891
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Sensor at x=1704479, y=2132468: closest beacon is at x=1749091, y=2000000
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Sensor at x=3904910, y=2080560: closest beacon is at x=3951198, y=2418718
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Sensor at x=657061, y=3898803: closest beacon is at x=595451, y=3788543
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Sensor at x=3084398, y=3751092: closest beacon is at x=3074353, y=3516891
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Sensor at x=2582061, y=972407: closest beacon is at x=1749091, y=2000000
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Sensor at x=2886721, y=3971936: closest beacon is at x=3074353, y=3516891
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Sensor at x=303399, y=548513: closest beacon is at x=-1010425, y=986825
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Sensor at x=3426950, y=2290126: closest beacon is at x=3951198, y=2418718
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Sensor at x=3132858, y=3592272: closest beacon is at x=3074353, y=3516891
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Sensor at x=3773724, y=3751243: closest beacon is at x=3568452, y=3274758
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Sensor at x=3987212, y=2416515: closest beacon is at x=3951198, y=2418718
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Sensor at x=61559, y=3806326: closest beacon is at x=595451, y=3788543
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Sensor at x=2693503, y=2291389: closest beacon is at x=2269881, y=2661753
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Sensor at x=3953437, y=2669220: closest beacon is at x=3951198, y=2418718
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Sensor at x=763035, y=3997568: closest beacon is at x=595451, y=3788543
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Sensor at x=3999814, y=2370103: closest beacon is at x=3951198, y=2418718
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Sensor at x=1290383, y=1696257: closest beacon is at x=1749091, y=2000000
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Sensor at x=3505508, y=2805537: closest beacon is at x=3568452, y=3274758
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Sensor at x=3276207, y=3323122: closest beacon is at x=3568452, y=3274758
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Sensor at x=2244609, y=3517499: closest beacon is at x=3074353, y=3516891
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Sensor at x=1370860, y=3436382: closest beacon is at x=595451, y=3788543
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Sensor at x=3831063, y=3042662: closest beacon is at x=3568452, y=3274758
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Sensor at x=551202, y=3971545: closest beacon is at x=595451, y=3788543
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Sensor at x=336629, y=2519780: closest beacon is at x=595451, y=3788543
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Sensor at x=2033602, y=2882628: closest beacon is at x=2269881, y=2661753
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Sensor at x=3939808, y=2478271: closest beacon is at x=3951198, y=2418718
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Sensor at x=1958708, y=2370822: closest beacon is at x=1749091, y=2000000
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Sensor at x=3039958, y=3574483: closest beacon is at x=3074353, y=3516891

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