88 lines
3.0 KiB
C#
88 lines
3.0 KiB
C#
#define Day15
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using System.Collections.Generic;
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using System.Diagnostics;
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using AoC2021;
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#if Day15
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var lines = File.ReadAllLines("day15/input");
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var cave = new int[lines.Length, lines[0].Length];
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lines.ForEachIndex((l, row) => l.ForEachIndex((c, col)=> cave[row, col] = int.Parse(c.ToString())));
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Console.WriteLine(Check(cave));
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int rowLength = cave.GetLength(0);
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int colLength = cave.GetLength(1);
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var largerCave = new int[lines.Length*5, lines[0].Length*5];
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for (int timeRow = 0; timeRow < 5; timeRow++) {
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for (int timesCol = 0; timesCol < 5; timesCol++) {
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for (int row = 0; row < rowLength; row++) {
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for (int col = 0; col < colLength; col++) {
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largerCave[rowLength * timeRow + row, colLength*timesCol + col] = ((cave[row, col] + timeRow + timesCol - 1) % 9) + 1;
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}
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}
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}
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}
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Console.WriteLine(Check(largerCave));
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long Check(int[,] caveToCheck) {
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var pos = new Point(0, 0);
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var end = new Point(caveToCheck.GetLength(0) - 1, caveToCheck.GetLength(1) - 1);
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var visitedLowest = new Dictionary<Point, long>() { { pos, 0 } };
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long min = 0;
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var sortedListReplacement = new Dictionary<long, List<PointWithVisited>>() { { 0, new List<PointWithVisited>() { new PointWithVisited(pos, new HashSet<Point>()) } } };
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while (true) {
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if (!sortedListReplacement.ContainsKey(min)) {
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min++;
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continue;
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}
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var minPoints = sortedListReplacement[min];
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if (minPoints.Count <= 0) {
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min++;
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continue;
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}
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var cur = minPoints.First();
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if (cur.point.Equals(end)) {
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return min;
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}
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minPoints.Remove(cur);
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var adjacent = GetAdjacent(cur.point, cur.visited, caveToCheck);
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foreach (var a in adjacent) {
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var riskLevel = min + caveToCheck[a.row, a.col];
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if (visitedLowest.ContainsKey(a) && visitedLowest[a] <= riskLevel) {
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continue;
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}
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visitedLowest[a] = riskLevel;
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AddToCheck(a, riskLevel, cur, sortedListReplacement);
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}
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}
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}
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void AddToCheck(Point p, long sum, PointWithVisited previous, Dictionary<long, List<PointWithVisited>> sortedListReplacement) {
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var copy = previous.visited.ToHashSet();
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copy.Add(previous.point);
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if (!sortedListReplacement.ContainsKey(sum)) {
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sortedListReplacement.Add(sum, new List<PointWithVisited>() {new PointWithVisited(p, copy)});
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return;
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}
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sortedListReplacement[sum].Add(new PointWithVisited(p, copy));
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}
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List<Point> GetAdjacent(Point cur, HashSet<Point> visited, int[,] caveToCheck) {
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return new List<Point>() {
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new Point(cur.row + 1, cur.col),
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new Point(cur.row - 1, cur.col),
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new Point(cur.row, cur.col + 1),
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new Point(cur.row, cur.col - 1),
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}.Where(p => p.row >= 0 && p.row < caveToCheck.GetLength(0) && p.col >= 0 && p.col < caveToCheck.GetLength(1))
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.Where(p => !visited.Contains(p))
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.ToList();
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}
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record PointWithVisited(Point point, HashSet<Point> visited);
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record Point(int row, int col);
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#endif |