#define Day15
using System.Collections.Generic;
using System.Diagnostics;
using AoC2021;
#if Day15

var lines = File.ReadAllLines("day15/input");
var cave = new int[lines.Length, lines[0].Length];
lines.ForEachIndex((l, row) => l.ForEachIndex((c, col)=> cave[row, col] = int.Parse(c.ToString())));

Console.WriteLine(Check(cave));

int rowLength = cave.GetLength(0);
int colLength = cave.GetLength(1);
var largerCave = new int[lines.Length*5, lines[0].Length*5];
for (int timeRow = 0; timeRow < 5; timeRow++) {
    for (int timesCol = 0; timesCol < 5; timesCol++) {
        for (int row = 0; row < rowLength; row++) {
            for (int col = 0; col < colLength; col++) {
                largerCave[rowLength * timeRow + row, colLength*timesCol + col] = ((cave[row, col] + timeRow + timesCol - 1) % 9) + 1;
            }
        }
    }
}

Console.WriteLine(Check(largerCave));

long Check(int[,] caveToCheck) {
    var pos = new Point(0, 0);
    var end = new Point(caveToCheck.GetLength(0) - 1, caveToCheck.GetLength(1) - 1);
    var visitedLowest = new Dictionary<Point, long>() { { pos, 0 } };
    long min = 0;
    var sortedListReplacement = new Dictionary<long, List<PointWithVisited>>() { { 0, new List<PointWithVisited>() { new PointWithVisited(pos, new HashSet<Point>()) } } };

    while (true) {
        if (!sortedListReplacement.ContainsKey(min)) {
            min++;

            continue;
        }
        var minPoints = sortedListReplacement[min];
        if (minPoints.Count <= 0) {
            min++;

            continue;
        }
        var cur = minPoints.First();
        if (cur.point.Equals(end)) {
            return min;
        }
        minPoints.Remove(cur);

        var adjacent = GetAdjacent(cur.point, cur.visited, caveToCheck);
        foreach (var a in adjacent) {
            var riskLevel = min + caveToCheck[a.row, a.col];
            if (visitedLowest.ContainsKey(a) && visitedLowest[a] <= riskLevel) {
                continue;
            }
            visitedLowest[a] = riskLevel;
            AddToCheck(a, riskLevel, cur, sortedListReplacement);
        }
    }
}

void AddToCheck(Point p, long sum, PointWithVisited previous, Dictionary<long, List<PointWithVisited>> sortedListReplacement) {
    var copy = previous.visited.ToHashSet();
    copy.Add(previous.point);
    if (!sortedListReplacement.ContainsKey(sum)) {
        sortedListReplacement.Add(sum, new List<PointWithVisited>() {new PointWithVisited(p, copy)});
        return;
    }
    sortedListReplacement[sum].Add(new PointWithVisited(p, copy));
}

List<Point> GetAdjacent(Point cur, HashSet<Point> visited, int[,] caveToCheck) {
    return new List<Point>() {
        new Point(cur.row + 1, cur.col),
        new Point(cur.row - 1, cur.col),
        new Point(cur.row, cur.col + 1),
        new Point(cur.row, cur.col - 1),
    }.Where(p => p.row >= 0 && p.row < caveToCheck.GetLength(0) && p.col >= 0 && p.col < caveToCheck.GetLength(1))
        .Where(p => !visited.Contains(p))
        .ToList();
}

record PointWithVisited(Point point, HashSet<Point> visited);
record Point(int row, int col);
#endif