AOC2022/day18/day18.go

package main

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

func main() {
	args := os.Args[1:]
	lines := helper.ReadTextFile(args[0])
	points := make(map[[3]int]bool, len(lines))
	for _, line := range lines {
		point := [3]int{}
		for j, number := range helper.StringSliceToIntSlice(strings.Split(line, ",")) {
			point[j] = number
		}
		points[point] = true
	}

	fmt.Println(removeOpenSurfacePointsWhichHaveNoConnectionToOutside(points))
	same := false
	pastLenPoints := len(points)
	for !same {
		removeOpenSurfacePointsWhichHaveNoConnectionToOutside(points)
		if pastLenPoints != len(points) {
			pastLenPoints = len(points)
		} else {
			same = true
		}
	}

	openSurfacesSum := 0
	for point, _ := range points {
		openSurfacesPoint := 6
		neighbors := getNeighbors(point)
		for _, neighbor := range neighbors {
			if points[neighbor] {
				openSurfacesPoint--
			}
		}
		openSurfacesSum += openSurfacesPoint
	}
	fmt.Println(openSurfacesSum)

}

func removeOpenSurfacePointsWhichHaveNoConnectionToOutside(points map[[3]int]bool) int {
	openSurfacesSum := 0
	openSurfacesPoints := make(map[[3]int]bool)
	for point, _ := range points {
		openSurfacesPoint := 6
		neighbors := getNeighbors(point)
		for _, neighbor := range neighbors {
			if points[neighbor] {
				openSurfacesPoint--
			} else {
				openSurfacesPoints[neighbor] = true
			}
		}
		openSurfacesSum += openSurfacesPoint
	}

	for point, _ := range openSurfacesPoints {
		if !checkIfPathToOutSideExists(points, point) {
			points[point] = true
		}
	}
	return openSurfacesSum
}

func getNeighbors(point [3]int) (neighbors [6][3]int) {
	directions := [][3]int{{0, -1, 0}, {+1, 0, 0}, {0, 1, 0}, {-1, 0, 0}, {0, 0, 1}, {0, 0, -1}}
	for i, direction := range directions {
		neighbors[i] = [3]int{point[0] + direction[0], point[1] + direction[1], point[2] + direction[2]}
	}
	return
}

func checkIfPathToOutSideExists(points map[[3]int]bool, startPoint [3]int) bool {
	activePoints := make(map[[3]int]bool)
	pointsCopy := deepCopyMap(points)
	activePoints[startPoint] = true
	foundAWay := false
	areaLimits := getAreaLimits(points)
	for !foundAWay && len(activePoints) > 0 {
		step(&pointsCopy, &activePoints, &foundAWay, areaLimits)
	}
	return foundAWay
}

func step(points *map[[3]int]bool, activePoints *map[[3]int]bool, foundAWay *bool, areaLimits [6]int) {
	activePoint := get_some_key(*activePoints)
	delete(*activePoints, activePoint)
	if (activePoint[0] > areaLimits[0] ||
		activePoint[0] < areaLimits[1]) &&
		(activePoint[1] > areaLimits[2] ||
			activePoint[1] < areaLimits[3]) &&
		(activePoint[2] > areaLimits[4] ||
			activePoint[2] < areaLimits[5]) {
		*foundAWay = true
		return

	}
	(*points)[activePoint] = true
	neighbors := getNeighbors(activePoint)
	for _, neighbor := range neighbors {
		if !(*points)[neighbor] {
			(*activePoints)[neighbor] = true
		}
	}
}

func getAreaLimits(points map[[3]int]bool) [6]int {
	highestX := -1
	lowestX := 999999
	highestY := -1
	lowestY := 999999
	highestZ := -1
	lowestZ := 999999
	for point, _ := range points {
		if point[0] > highestX {
			highestX = point[0]
		}
		if point[0] < lowestX {
			lowestX = point[0]
		}
		if point[1] > highestY {
			highestY = point[1]
		}
		if point[1] < lowestY {
			lowestY = point[1]
		}
		if point[2] > highestZ {
			highestZ = point[2]
		}
		if point[2] < lowestZ {
			lowestZ = point[2]
		}
	}
	return [6]int{highestX, lowestX, highestY, lowestY, highestZ, lowestZ}
}

func get_some_key[T any](m map[[3]int]T) [3]int {
	for k := range m {
		return k
	}
	return [3]int{-1, -1, -1}
}

func deepCopyMap(points map[[3]int]bool) map[[3]int]bool {
	tmpValves := make(map[[3]int]bool)
	for k, v := range points {
		tmpValves[k] = v
	}
	return tmpValves
}