You watch the Elves and their sleigh fade into the distance as they head toward the North Pole.

Actually, you're the one fading. The falling sensation returns.

Read the full puzzle.

namespace AdventOfCode.Y2018.Day11;

[ProblemName("Chronal Charge")]
class Solution : Solver {

    public object PartOne(string input) {
        var res = Solver(int.Parse(input), 3);
        return $"{res.xMax},{res.yMax}";
    }

    public object PartTwo(string input) {
        var res = Solver(int.Parse(input), 300);
        return $"{res.xMax},{res.yMax},{res.dMax}";
    }

    (int xMax, int yMax, int dMax) Solver(int gridSerialNumber, int D) {
        var gridOriginal = new int[300, 300];
        for (var irow = 0; irow < 300; irow++) {
            for (var icol = 0; icol < 300; icol++) {
                var x = icol + 1;
                var y = irow + 1;
                //  Find the fuel cell's *rack ID*, which is its *X coordinate plus 10*.
                var rackId = x + 10;
                // - Begin with a power level of the *rack ID* times the *Y coordinate*.
                var powerLevel = rackId * y;
                // - Increase the power level by the value of the *grid serial number* (your puzzle input).
                powerLevel += gridSerialNumber;
                // - Set the power level to itself multiplied by the *rack ID*.
                powerLevel *= rackId;
                // - Keep only the *hundreds digit* of the power level (so `12*3*45` becomes `3`; numbers with no hundreds digit become `0`).
                powerLevel = (powerLevel % 1000) / 100;
                // - *Subtract 5* from the power level.
                powerLevel -= 5;

                gridOriginal[irow, icol] = powerLevel;
            }
        }

        var maxTotalPower = int.MinValue;
        var yMax = int.MinValue;
        var xMax = int.MinValue;
        var dMax = int.MinValue;

        var grid = new int[300, 300];
        for (var d = 1; d <= D; d++) {
            for (var irow = 0; irow < 300 - d; irow++) {
                for (var icol = 0; icol < 300; icol++) {
                    grid[irow, icol] += gridOriginal[irow + d - 1, icol];
                }
            }

            for (var irow = 0; irow < 300 - d; irow++) {
                for (var icol = 0; icol < 300 - d; icol++) {
                    var totalPower = 0;

                    for (var i = 0; i < d; i++) {
                        totalPower += grid[irow, icol + i];
                    }

                    if (totalPower > maxTotalPower) {
                        maxTotalPower = totalPower;
                        yMax = irow + 1;
                        xMax = icol + 1;
                        dMax = d;
                    }
                }
            }
        }
        return (xMax, yMax, dMax);
    }

}

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