AOC2022/day15/day15.go

package main

import (
	"AOC2022/helper"
	"fmt"
	"os"
	"strings"
)

func main() {
	args := os.Args[1:]
	lines := helper.ReadTextFile(args[0])
	points := getPoints(lines)
	//scannedXPoints := make(map[int]bool)
	scannedPoints := getScannedPointsForTagetY(points, [2]int{2000000, 2000000}, [2]int{-100000000, 100000000})
	fmt.Println(len(scannedPoints) - 1)
	part2(points)
}

// Fichtes Solution
func part2(points [][2][2]int) {
	scannerWithDistances := [][3]int{}
	for _, scannedPoint := range points {
		distance := helper.ManHattanDistance(scannedPoint[0], scannedPoint[1])
		scannerWithDistances = append(scannerWithDistances, [3]int{scannedPoint[0][0], scannedPoint[0][1], distance})
	}
	startPoint := [2]int{0, 0}
	finish := false
	for !finish {
		scanner := checkIfPointIsInScannerReach(startPoint, scannerWithDistances)
		if scanner[2] == -1 {
			finish = true
		} else {
			distanceToTargetY := helper.Abs(scanner[1] - startPoint[1])
			widthOnTargetY := helper.Abs(distanceToTargetY - scanner[2])
			newXValue := scanner[0] + widthOnTargetY + 1
			if newXValue > 4000000 {
				startPoint = [2]int{0, startPoint[1] + 1}
			} else {
				startPoint[0] = newXValue
			}
		}
	}
	fmt.Println(startPoint[0]*4000000 + startPoint[1])
}

func checkIfPointIsInScannerReach(point [2]int, scanners [][3]int) [3]int {
	for _, scannerWithDistance := range scanners {
		if helper.ManHattanDistance(point, [2]int{scannerWithDistance[0], scannerWithDistance[1]}) <= scannerWithDistance[2] {
			return scannerWithDistance
		}
	}
	return [3]int{0, 0, -1}
}

func getScannedPointsForTagetY(points [][2][2]int, targetyRange [2]int, targetxRange [2]int) map[[2]int]bool {
	scannedYPoints := make(map[[2]int]bool)
	for _, pointPair := range points {
		sensor := pointPair[0]
		beacon := pointPair[1]
		distanceToSensor := helper.ManHattanDistance(sensor, beacon)
		distanceToTargetYLowest := helper.Abs(sensor[1] - targetyRange[0])
		distanceToTargetYHighest := helper.Abs(sensor[1] - targetyRange[1])
		if sensor[1] >= targetyRange[1] && distanceToSensor >= distanceToTargetYHighest {
			i := targetyRange[1]
			for i >= targetyRange[1]-(distanceToSensor-distanceToTargetYHighest) && i >= targetyRange[0] {
				setPointsForTargetY(distanceToSensor, i, targetxRange, sensor, &scannedYPoints)
				i--
			}
		}
		if sensor[1] <= targetyRange[0] && distanceToSensor >= distanceToTargetYLowest {
			i := targetyRange[0]
			for i <= targetyRange[0]+(distanceToSensor-distanceToTargetYLowest) && i <= targetyRange[1] {
				setPointsForTargetY(distanceToSensor, i, targetxRange, sensor, &scannedYPoints)
				i++
			}
		}
		if sensor[1] >= targetyRange[0] && sensor[1] <= targetyRange[1] {
			i := sensor[1]
			for i <= targetyRange[1] && i <= sensor[1]+distanceToSensor {
				setPointsForTargetY(distanceToSensor, i, targetxRange, sensor, &scannedYPoints)
				i++
			}
			i = sensor[1]
			for i >= targetyRange[0] && i >= sensor[1]-distanceToSensor {
				setPointsForTargetY(distanceToSensor, i, targetxRange, sensor, &scannedYPoints)
				i--
			}
		}
	}
	return scannedYPoints
}

func setPointsForTargetY(distanceToSensor, targetY int, targetxRange, sensor [2]int, scannedYPoints *map[[2]int]bool) {
	distanceToTargetY := helper.Abs(sensor[1] - targetY)
	widthOnTargetY := helper.Abs(distanceToTargetY - distanceToSensor)
	i := sensor[0] - widthOnTargetY
	if i < targetxRange[0] {
		i = targetxRange[0]
	}
	for i <= sensor[0]+widthOnTargetY && i <= targetxRange[1] {
		(*scannedYPoints)[[2]int{i, targetY}] = true
		i++
	}
}

func getPoints(lines []string) [][2][2]int {
	points := make([][2][2]int, len(lines))
	for i, line := range lines {
		intPair := [2][2]int{}
		stringParts := strings.Split(line[12:], ":")
		sensorStringNumbers := helper.StringSliceToIntSlice(strings.Split(stringParts[0], ", y="))
		beaconStringNumbers := helper.StringSliceToIntSlice(strings.Split(strings.ReplaceAll(stringParts[1], " closest beacon is at x=", ""), ", y="))
		intPair[0] = [2]int{sensorStringNumbers[0], sensorStringNumbers[1]}
		intPair[1] = [2]int{beaconStringNumbers[0], beaconStringNumbers[1]}
		points[i] = intPair
	}
	return points
}