aoc24/day12/main.go

package main

import (
	"fmt"
	"slices"
	"sync"

	"git.mstar.dev/mstar/aoc24/util"
	"git.mstar.dev/mstar/goutils/sliceutils"
)

type Block struct {
	Char    rune
	Counter int
}

type Coordinate struct {
	X, Y int
}

type Area struct {
	area [][]Block //Y, X
	rwl  sync.RWMutex
}

func convertLinesIntoBlockMap(lines []string) Area {
	out := [][]Block{}
	for _, line := range lines {
		bordLine := []Block{}
		for _, char := range line {
			// All blocks have four different blocks bordering in the beginning
			bordLine = append(bordLine, Block{char, 0})
		}
		out = append(out, bordLine)
	}

	return Area{out, sync.RWMutex{}}
}

func (c Coordinate) Left() Coordinate {
	return Coordinate{c.X - 1, c.Y}
}

func (c Coordinate) Right() Coordinate {
	return Coordinate{c.X + 1, c.Y}
}

func (c Coordinate) Up() Coordinate {
	return Coordinate{c.X, c.Y - 1}
}

func (c Coordinate) Down() Coordinate {
	return Coordinate{c.X, c.Y + 1}
}

func (a *Area) Get(x, y int) *Block {
	if y < 0 || y >= len(a.area) || x < 0 || x >= len(a.area[0]) {
		return nil
	}
	a.rwl.RLock()
	defer a.rwl.RUnlock()
	return &a.area[y][x]
}

func (a *Area) GetCoord(c Coordinate) *Block {
	if c.Y < 0 || c.Y >= len(a.area) || c.X < 0 || c.X >= len(a.area[0]) {
		return nil
	}
	a.rwl.RLock()
	defer a.rwl.RUnlock()
	return &a.area[c.Y][c.X]
}

func (a *Area) CountEdgesAtCoord(c Coordinate) int {
	block := a.GetCoord(c)
	if block == nil {
		return 1
	}
	acc := 0
	left := a.GetCoord(c.Left())
	if left == nil || left.Char != block.Char {
		acc++
	}
	right := a.GetCoord(c.Right())
	if right == nil || right.Char != block.Char {
		acc++
	}
	up := a.GetCoord(c.Up())
	if up == nil || up.Char != block.Char {
		acc++
	}
	down := a.GetCoord(c.Down())
	if down == nil || down.Char != block.Char {
		acc++
	}

	return acc
}

func (a *Area) CollectRegion(at Coordinate) []Coordinate {
	coords := []Coordinate{at}
	self := a.GetCoord(at)
	self.Counter++

	left := a.GetCoord(at.Left())
	if left != nil && left.Char == self.Char && left.Counter != self.Counter {
		coords = append(coords, a.CollectRegion(at.Left())...)
	}
	right := a.GetCoord(at.Right())
	if right != nil && right.Char == self.Char && right.Counter != self.Counter {
		coords = append(coords, a.CollectRegion(at.Right())...)
	}
	Up := a.GetCoord(at.Up())
	if Up != nil && Up.Char == self.Char && Up.Counter != self.Counter {
		coords = append(coords, a.CollectRegion(at.Up())...)
	}
	Down := a.GetCoord(at.Down())
	if Down != nil && Down.Char == self.Char && Down.Counter != self.Counter {
		coords = append(coords, a.CollectRegion(at.Down())...)
	}

	return coords
}

func (a *Area) GetAllAreas() [][]Coordinate {
	areas := [][]Coordinate{}
	for iy, line := range a.area {
	inner:
		for ix := range line {
			tmp := a.CollectRegion(Coordinate{ix, iy})
			for _, a := range areas {
				if sliceutils.CompareUnordered(a, tmp) {
					continue inner
				}
			}
			areas = append(areas, tmp)
		}
	}

	return areas
}

// Filter for coordinates where a section borders on a different section
func filterBorderLeft(coords []Coordinate, area *Area) []Coordinate {
	return sliceutils.Filter(coords, func(t Coordinate) bool {
		self := area.GetCoord(t)
		other := area.GetCoord(t.Left())
		return other == nil || self.Char != other.Char
	})
}

func filterBorderRight(coords []Coordinate, area *Area) []Coordinate {
	return sliceutils.Filter(coords, func(t Coordinate) bool {
		self := area.GetCoord(t)
		other := area.GetCoord(t.Right())
		return other == nil || self.Char != other.Char
	})
}

func filterBorderUp(coords []Coordinate, area *Area) []Coordinate {
	return sliceutils.Filter(coords, func(t Coordinate) bool {
		self := area.GetCoord(t)
		other := area.GetCoord(t.Up())
		return other == nil || self.Char != other.Char
	})
}

func filterBorderDown(coords []Coordinate, area *Area) []Coordinate {
	return sliceutils.Filter(coords, func(t Coordinate) bool {
		self := area.GetCoord(t)
		other := area.GetCoord(t.Down())
		return other == nil || self.Char != other.Char
	})
}

func splitSameX(coords []Coordinate) [][]Coordinate {
	axis := [][]Coordinate{}
	axisLabeled := map[int][]Coordinate{}
	for _, coord := range coords {
		axisLabeled[coord.X] = append(axisLabeled[coord.X], coord)
	}
	for _, subCoords := range axisLabeled {
		axis = append(axis, subCoords)
	}
	return axis
}

func splitSameY(coords []Coordinate) [][]Coordinate {
	axis := [][]Coordinate{}
	axisLabeled := map[int][]Coordinate{}
	for _, coord := range coords {
		axisLabeled[coord.Y] = append(axisLabeled[coord.Y], coord)
	}
	for _, subCoords := range axisLabeled {
		axis = append(axis, subCoords)
	}
	return axis
}

func countUniqueEdgesLeft(coords []Coordinate, area *Area) int {
	acc := 0
	leftBorders := filterBorderLeft(coords, area)
	// fmt.Printf("All left borders: %v\n", leftBorders)
	bordersLeftPerAxis := splitSameX(leftBorders)
	// fmt.Printf("Same left: %v\n", bordersLeftPerAxis)
	for _, borders := range bordersLeftPerAxis {
		// acc++
		slices.SortFunc(borders, func(a, b Coordinate) int { return a.Y - b.Y })
		// fmt.Printf("Axis left: %v\n", borders)
		prevY := -500
		for _, coord := range borders {
			if coord.Y-1 != prevY {
				acc++
			}
			prevY = coord.Y
		}
	}
	fmt.Printf("Left borders: %v\n", acc)
	return acc
}

func countUniqueEdgesRight(coords []Coordinate, area *Area) int {
	acc := 0
	bordersLeftPerAxis := splitSameX(filterBorderRight(coords, area))
	// fmt.Printf("Same right: %v\n", bordersLeftPerAxis)
	for _, borders := range bordersLeftPerAxis {
		slices.SortFunc(borders, func(a, b Coordinate) int { return a.Y - b.Y })
		// acc++
		prevX := -500
		for _, coord := range borders {
			if coord.Y-1 != prevX {
				acc++
			}
			prevX = coord.Y
		}
	}
	fmt.Printf("Right borders: %v\n", acc)
	return acc
}

func countUniqueEdgesUp(coords []Coordinate, area *Area) int {
	acc := 0
	bordersLeftPerAxis := splitSameY(filterBorderUp(coords, area))
	fmt.Printf("Same up: %v\n", bordersLeftPerAxis)
	for _, borders := range bordersLeftPerAxis {
		// acc++
		slices.SortFunc(borders, func(a, b Coordinate) int { return a.X - b.X })
		fmt.Printf("Sorted up axis: %v\n", borders)
		prevX := -500
		for _, coord := range borders {
			if coord.X-1 != prevX {
				acc++
				fmt.Println("Up inc")
			}
			prevX = coord.X
		}
	}
	fmt.Printf("Up borders: %v\n", acc)
	return acc
}

func countUniqueEdgesDown(coords []Coordinate, area *Area) int {
	acc := 0
	bordersLeftPerAxis := splitSameY(filterBorderDown(coords, area))
	for _, borders := range bordersLeftPerAxis {
		// acc++
		slices.SortFunc(borders, func(a, b Coordinate) int { return a.X - b.X })
		fmt.Printf("Same down: %v\n", bordersLeftPerAxis)
		prevX := -500
		for _, coord := range borders {
			if coord.X-1 != prevX {
				fmt.Println("Bigdiff")
				acc++
			}
			prevX = coord.X
		}
	}
	fmt.Printf("Down borders: %v\n", acc)
	return acc
}

func countUniqueEdges(coords []Coordinate, area *Area) int {
	return countUniqueEdgesLeft(
		coords,
		area,
	) + countUniqueEdgesRight(
		coords,
		area,
	) + countUniqueEdgesUp(
		coords,
		area,
	) + countUniqueEdgesDown(
		coords,
		area,
	)
}

func main() {
	area := convertLinesIntoBlockMap(util.FileContentToNonEmptyLines(util.LoadFileFromArgs()))
	allAreas := area.GetAllAreas()

	totalAcc := 0
	for _, subArea := range allAreas {
		tmp := 0
		for _, coord := range subArea {
			tmp += area.CountEdgesAtCoord(coord)
		}
		totalAcc += tmp * len(subArea)
	}
	fmt.Printf("Task 1: %d\n", totalAcc)
	// fmt.Println(countUniqueEdges(allAreas[2], &area))
	// return
	edgesAcc := 0
	for _, subArea := range allAreas {
		tmp := countUniqueEdges(subArea, &area)
		fmt.Printf(
			"Area %s has %d edges with len %d\n",
			string(area.GetCoord(subArea[0]).Char),
			tmp,
			len(subArea),
		)
		// fmt.Println(tmp * len(subArea))
		edgesAcc += tmp * len(subArea)
	}
	fmt.Printf("Task 2: %d\n", edgesAcc)
}

// c2: l14 e22
// f3: l10 e12
// e7: