[2020-12-11] Add solutions for day11

Makefile

@@ -33,6 +33,8 @@ day10:
 	go run main.go day10 input
 
 day11:
+	go run main.go day11 input
+
 day12:
 day13:
 day14:

day11/example.txt

@@ -0,0 +1,10 @@
+L.LL.LL.LL
+LLLLLLL.LL
+L.L.L..L..
+LLLL.LL.LL
+L.LL.LL.LL
+L.LLLLL.LL
+..L.L.....
+LLLLLLLLLL
+L.LLLLLL.L
+L.LLLLL.LL

day11/input.txt

@@ -0,0 +1,90 @@
+LLLLLLL.LLLLLLLLLLLL.LL.L.LLLLLLLLLLLLLLLLLL.LLLLL.LLLLLLL.LLLLLLLLL.LLLL.LLLLL.LLLLLLLLLLLLL
+LLLLLLL.LLLLLLLLLLLL.LLL..LLLLLLLLLLLLLLLLLLLLLLL..LLLL.LLLLLLLLLLLLLLLLLLLLLLL.LLLLLLL.LLLLL
+LLLLLLLLLLLLLL.LLLLLLLLLL.LLLLLLLL.LLLLLLLLL.LLLLL.LLLLLLL.LLLLLLLLL.LLLL.LLLLLLLLLLLLLLLLLLL
+LLLLLLLLLLLLLL.LLLLL.LLLLLLLLLLLLLLLLLL.LLLL.LLLLLLLLLLL.LLLLLLLLLLLLLLLL.LLLLL.LLLLLLLL.LLLL
+LLLLLLL.LLLLLL.LLLLL.LLLLLLLLLLLLLLLLLLLLLLL.LLLLL.LLLLLLL.LLLLLLLLLLLLLL.LLLLL.LLLLLLL.LLLLL
+LLLLLLL.LLLLLL.L.LLLLLLLL.L.LLLLLL.LLLLLL.LL.LLLLL.LLLLLLLLLLLLLLLLL.LLLL.LLLLL.LLLLLLLLLLLLL
+.L.....L...L.....LL..L...LLL.L.LL..LLL..LL.LLL...LLLL..L......L..........L...L..LL..LLL.L...L
+LLLLLLLLLLLLLLLLLLLL.LLLLLLLLLLLLLLLLLLL.LLLLLLLLL.LLLLLLL.LLLLLLLLL.LLLL.LLLLL.LLLLLLL.LLLLL
+LLLLLLL.LLLLLL.LLLLL.L.LLLLLLLLLLL.LLLLLLLLL.LLLLLLLLLLLLL.LLLLLLLLL.LLLLLLL.LL.LLLLLLLLLLLLL
+LLLL.LL.LLLLLL.LLLL.LLLLL.LLLLL.LLLLLLLLLLLL.LLLLLLLLLLLLL.LLLLLLLLL.LL.LLLLL.LLLLLLLLL.LLLL.
+LLLLLLL.LLLLLL.LLLLL..LLL.LLLLLL.L.LLLLLLLLL.LLLL..LLLLLLL.L.L.LLLLL.LLLLLLLLLL.LLLLLLLLLLLLL
+LLL.LLL.LLLLLLLLLL.L.LLLL..LLLLLLLLLL.LL.LL.LLLLLL.LLLLL.LLLLLLLLLLL.LLLL.LLLLL.LLLLLLL.LLLLL
+LLLLLLL.LLLLLLLLLLLLLLLLLLLLLLL.LLLLLLLLLL.L.LLLLL.LLLLLLL.LL.LLLLLLLLLLL.LLLLL.LLLLLLLLLLLL.
+LLLLLLL.LLLLLLLLLLLLLLLLL.LLLLLLLLLLLLLLLLLL.LLLLL.LLLLLLLLLLLLLLLLLLLLLL.LLLLL.LLLLLLL.LLLLL
+L...L..LLL.....L.LL..L.LLLL....LLLL.....L.L.LLL..L.L...LL.LL....L..LLLL..L..L.LL...L.L.....L.
+LLLLLLL.LLLLLLLLLLLLLLLLL.LLLLLLLL.LLLLLLLLL.LLL.L.LLLLLLLLLLLLLLLLL.LLLL.LLLLL.LLLLLLL.LLLLL
+LLLLLLL.LLLLLL.LLLLL.LLLL.LLLLLLLL.LLLLLLLLL.LLLLLLLLLLLLLLLLLLL.LLL.LLLLLLL.LLLLLLLLLL.LLLLL
+LLLLLLL.LLLLLLLLLLLL.LLLL.LLLL.LLL.LLLLLLLLLLLLLLLLLLL.LLLLLLLLLLLLL.L.LL.LLLLL.LLLLLLLLLLLLL
+LLLLLLL..LLLLLLLLLLL.LLLLLLLLLLLLL.LLLLLLLLLLLLLLL.LLLLLLL.LLLLLLLLLLLLLL.LLLLL.LLLLLLLLLLLLL
+.........LL..LL..LL..LL.....L..L..LL.............L...L....LLLL...LL...LLL..L...LLL.....L....L
+LLLLLLLLLLLLLLLLLLLL.LLLLLLLLLLLLLLLLLLLLLLL.LLLLLLLLLLLLLLLLLLLLLLL.LLLL.LLLLL..LLLLLL.L.LLL
+LLLLLLLLLLLLLL.LLLLLLLLLL.LLLLLLLL.LLLLLLLLLLLLLLL.LLLLLLL.LLLLLLLLLLLLLLLLLLLL.LLLLLLLLLLLLL
+LLLLLLL.LL.LLL.LLLLL.LLLL.LLLLLLLL.LLLLLLLLLLLLLLL.LLLLLLL.LLLLLLLLL.LLLLLLLLL.LLL.LLLLLLLLLL
+LLLLLLL.LLLLLLLLLLL.LLLLLLLLLLLLLL.LLLLLLLLL.LLLLLLLLLLLLL.LLLLLLLLL.LLLL.LL.LL..LLLLLLLLLLLL
+LLLLLLL.LLLLLLLLLLLL.LLLL.LLLLLLLLLL.LLLLLLL.LLLLL.LLLLLLL.LLLLLLLLL.LLLL.LLLLL.LLLLLLL.LLLLL
+LLLLLLLLLLL.L.LLLLLL.LLLLLLLLLLLLLLLLLLLLLLL.LLLLLLLLLLLLL.LLLLLLLLL.LLLLLLLLLLLLLLLLLLLLLLLL
+...L.L..L.L.L....L....L.LLL.L.L.L..L..L...L....L......L.......L..L.L.L..L..LL...L....L....LL.
+LLLLLLL.LLLLLL.LLLLLLLLLLLLLLLLLLLLLLLLLLLLL.LLLLLLLLLLLLL.LLLLLLLLL.L.LL.LL.LL.LLLLLLLLLLLLL
+LLLLLLL.LLLLLL.LLLLL.LLLL.LLLLLLLL.LLLLLLL.L.LLLLL.LLLLLLL.LLLLLLLLL.LLLL.LLLLL.LLLLLLL.LLLLL
+LLLLLLLLLLLLLL.LLLLL.LLLL.LLLLLLLLLLLLLLLLLLLLLLLL.LLLLLLL.LLLLLLLLL..LLL..LLLL.LLLL.LL.LLLLL
+LLLLLLLLLLLLLLLLLLLL.LLLLLLL.LLLLL.LLLLLLLLL.LLLLL.L.LLLL.LLLLLLLLLLLLLLLLLLLLLLLLLLLLL.LLLLL
+LLLLLLLLLLLLLL.LLLLLLLLLL.LLLLLLLLLLLLLLLLLL.LLLLL.LLLLLLL.LLLLLLLLL.LLLL.LLLLLLLLLLLLL..LLLL
+LLLLLLL.LLLLLLLLLLLL.LLLLLLLLLLLLL.LLLLLLLLL.LL.LLLLLLLLLL.LLLLLLLLL.LLLLLLLLLL.LLLLLLL.LLLLL
+..LLLLL...LL...L..L.....L.LL.L....L.L..LL.L......L.L.L..L...L.L..L..L..L.LL..L.L.L..L.....L..
+LLLLLLL.LLLLLL.LLL.L.LLLL.LLLLLLLLLLLLLLLLLL.LLLLL.LLLLLLLLLLLLLLLLLLLLLL.LLLLL.LLLLLLL.LLLLL
+LLLLLLL.LLL.LL.LLLLL.LLLL.LLLLLLLL.LLLLLL.LL.LLLL..LLLLLL.LLLLLLLLLL.LLLL..LLLL.LLLLLLL.LLLLL
+LLLLLLLLLLLLLL.LLLLL.LLLL.LLLLLLLL.LLLLLLLLL.LLLLL.LLLLLLL.LLLLLLLLL.LLLLLLLLLL.LLLLLLL.LLLLL
+.LLLLLL.LLLLLL.LLLLL.LLLLLLLLL.LLL.LLLLLLL.L.LLLLLLLLLLLLLLLL.LLLLLL.LLLL.LLLLL.LLLLLLL.LLLLL
+LLLLLLL.LLLLLL.LLLLLLLLLL.LLLLLLLL.LLLLLLLLL.LLLL.LLLLLLLL.LLLLLLLLL.LLLL.LLLLL.LLLLLLLLLLLLL
+LLLLLLL.LLL.LL.LLLLLLLLLL.LLLLLLLL.LLLLLLLLL.LLLLL.LLLL.LL.LL.LLLLLLLLLLLLLL.LL.LLLL.LL.LLLL.
+LLLLLLL.LLLLLL.LLLLLLLLLL.L..LLLLLLLLLLLLLLL.LLLLLLLLLLLL.LLLLLLLLLLLLLLL.LLLLL.LLLLLLL.LLLLL
+LL......LLL...L.LL...LL..LLLL.L..L.........L..L.....L..L......L..L...LLL.....LL.......LL.....
+LLLLLLL.LLLLLL.LLLLL.L.LL.LLLLLLLL.LLLL.LLLLL.L.LLLLLLLLLL.LLLLLLLLL.LLLLLLLLL..LLLLLLLLLLLLL
+LLLLLLL.L.LLLL.LLLLL.LLLLLLLLLL.LLLLLLLLLLLLLLLLLLLLLLLLLL.LLLLLLLLL.LLLL.LL.LL.LLLLLLLLLLLLL
+LLLLLLL.LLLLLL.LLLLLLLLLL..LLLLLLLLLLLLLLLLLLLLLLL.L.LLLLL.LLLLLLLLL.LLLLLLLLLLLLLLLLLLLLLLLL
+LLLLLLL.LLLL.LLLLLLLLLLLLLLLLLLLLLLLLLLLLLLL.LLLLL.LLLLLLL.LLLLLLLLL.LLLL.LLLLL.L.LLLLLLLLLLL
+LLLLLLL.LLLLLL.LLLLL.LLLL.LLL.LLLLLLLLLLLLLL.LLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLL.LLLLLLLLLLLLL
+LLLLLLL.LLLLLL.LLLLL.LLLL.LLLLLLLLL.LLLLLLLLLLLLLL.LLLLLLL.LLLLLLLLL.LLL.LLLLLLLLLLLLLLLLLLLL
+LLLLLLL.LLLLLL.LLL.L.LLLL.LLLLLLLL.LLLLLLLLL.LLLLLLLLLLLLL.LLLLLLLLL.LLLL.LLLLL.LLLLLLLLLLLLL
+L....L.L..L.L....L..L.L...L.....L..LL...L.L.L.L.LL..L....LL..LL....L.L.......LLL..LLL...LL..L
+LLLLLLLLLLLLLLLLLLLLLLLLL.LLLLLLLL.LLLLLLL.LLLLLLLLLLLLLL..LLLLLLLLL.LLLL..LLLL.LLLLLLLLLLLLL
+LLLLLLLLLLLLLL.LLLLL.LLLL.LLLLLLLLLLLLLLLLLL.LLLLL.LLLLLLL.LLLLLLLLLL.LLLLLLLLL.LLLLLLL.LLLLL
+LLLLLLL.LLLLL..LLLLL.LLLLLLLLLLLLL.LLLLLL.LL..LLLLLLLLLLLLLLLLLLLLLL.LLLL.LLLLL.LLLLLLLLL.LLL
+L.L.LLLLLLLLLL.LLLLL.LLLL.LLLLL.LL.LLLLLLLLL.LLLLL.LLLLLLL.LLLLL.LLL.LLLL.LLLLLLLLLLLLLLLLLLL
+LLLLLLL.LLLLLL.LLLLLLLLLL.LLLLLLLLLLLLLLLLLLLLLLLLL.LLLLLL.LLLLLLLLLLLLLL.LLLLL.LLLLLLL.LLLLL
+LLLLLLL.LLLLLLLLLLLL.LLLL.LLLLLLLL.LLLLLLLLL.LLLLL.LLLLLLL.LLLLLLLLL.LLLL.LLLLLLLLLLLLL.LLLLL
+LLLLLLLLLLLLLL.LLLLL.LLLL.LLLLLLLL.LLLLLLLLL.LLLLL.LLLLLLL.LLLLLLLLL.LLLL.LLLLL.LLLLLLL.LLLLL
+LLLLLLL.L.LLLLLLLLLL.LLLLL.LLLLLLLLLLLLLLLLL.LLLLL.LLLLLLL.LLLL.LLLL.LLLL.LLLLLLLLLLLLLLLLLL.
+LL.L.LLLLLLLLL.LLLLLLLLLL.LLLLLLLLLLLLLLLLLL.LLLLL.LLLLLLL.LLLLLLLLL.LLLL.LLLLLLLLLLLLL.LLLLL
+...L..L..L..L....LLL..L.LL....L........L.......L.L.LL.L........L...LLLL....LL.......L.LL..L.L
+LLLLLLLLLLLLLL.LLLLLLLLLL.LLLLLLLLLLLLLLLLLL.LLLLLLLLLLLLL.LLLLLLLLLLLLLLLLLLLL.LLLLLLLLLLLLL
+LLLLLLL.LLLLLL.LL.LL.LLLLLLLLLL.LL.LLLLLLLLL.LLLLL.LLL..LLLLLLLLLLLL.LLLL..LL.L.LLLLLLL.LLLLL
+LLLLLLL.LLLLLLLLLLLL.LLLL.LLLLLLLL.LLLLLLL.L.LL.LL.LLLLLLL.LLLLLLLLLL.LLL.LLLLL.LLLLLLL.LLLLL
+LLLLLLLLLLL.LL.L.LLL.LLLL.LLLLLLL..LLLLLLLLL.LLLLLL.LLLLLLLLLLLLLLLL.LLLL..LLLLLLLLLLLL.LLLLL
+LLLLLLLLLLLLLLLLLLLL.LLLLLLLLLLLLLLLLLLLLLLLLLLLLL.LLLLLLL.LLLLLLLLLLLLLLLLLLLL.LLLLL.L.LLLLL
+LLLLLLL.LLLLLL.LLLLLLLLLL.LLLLLLLL.L.LLLLLLL.LLLLLLLLLLLLL.LLLLLLLLL.LLLL.LLLLL.LLLLLLLLLLLLL
+LLLLLLLLLLLLLL.LLLLL.LLLL.LLLLLLLL.LLLLLLLLLLLLLLL.LLLLLLLLLLLLLLLLL.LLLL.L.LLL.LLLLLLL..LLLL
+LLLLLLL.LLLLLL.LLLLL.LLLL.LLLLLLLLLLLLLLLLLLLLLLLL.LLLLLLL.LLLLLLLLL.L.LL.L.LLL.LLLLLLL.LLLL.
+....LLLL.L..L....LL..L.....LL..........LL.....L.L..LL.LL......L.L.L.L....L.LL.L.L..L......L..
+LLLLLLLLLLLLLL.LLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLL.LLLLLLLLLLLLLLLLLLLLLL.LLLLLLLLLLL.LLLLLLL
+LLLLLLLLLLL.LLLLLLLL.LLLL.LLLLLLLL.LLL.LLLLL.LLLL..LLLLLLLLLLLLLLLLL.LLLL.LLLLL..LLLLLL.LLLLL
+LLLLLLLLLLLLLL.LLLLL.LLLL.LLLLLLLLLLLLLLL.LL.LLLLL.LLLLLLLLLLLLLLLLLLLLLL.LLLLL.LLLLLLL.LL.LL
+LLLLLLL.LLLLLL.LLLLL.LLLL.LLLLLLLL.LLLLLLLLLLLLLLL.LLLLLLL.LLLLLLLLL.LLLL.LLLLLLL.LLLLLLLLLL.
+LLLLLLLLLLLLLL.LLLLLLLLLL.LLLLLLLL..LLLLLL.LLLLLLL.LL.LLLLLLLLLLLLLLLLLLLLLLLLL.L.LLLLL..LLLL
+LLL.LLLLLLLLLLLLLLLLLLLLL.LLLLLLLLLLLLLLLLLLLLL.LL.LLLLLLL.LLLLLLL.L.LLLL.LLLLL.LLLLLLL.LLLLL
+LLLLLLLLLLLLLL.LLLLL.LLLL.LLLLLLLL.LLLL.LLLL.LLLLL.LLLL.LLLLLLLLLLLL.LLLLLLLLLL.LLLLLLL.LLLLL
+LLLLLL..LLLLLLLLLL.L.LLLL.LLLLLLLLLLLLLLLLLLLLLLLL.LLLLLLL.LLLLLLLLL.LLLLLLLLLL.LLLLLLL.L.LLL
+LLLLLLLLLL.LLLLLLLLL.LL.L.LLLLLLLL.LLLLLLLLL.LLLLLLLLLLLLL.LLLLLLLLL.LLLL.LLLLL.LLL.LLL.LLLLL
+L.L...L....LL.L....LL..L...L...LL.L.............LLLLL..LL........LLL.L....L.L...L.L...LLL.LL.
+LLLLLLL.LLLLLL.LLLLLLLLLL.LLLLLLLL.LLLLLLLLL.LLLLL.LLLLLLL.LLLLLLLLL.LLLL.LLLLLL.LLLLLL.LLLLL
+LL.LLLL.LLLLLLLLLLLL.LLLLLLLLLLLLLLLLLL.LLLL.LLLLL.LLLLLLL.L.LLL.LLLLLLLLLLLLLLLLLLLLLLLLLLLL
+LLLLLLL.LLLLLL.LLLLL.LLLLLLLLLLLLL.LLLLLLLLL.LLLLL.LLLLLLLLLLLLLLLLL.LLLL.LLLLL.LLLLLLLLLLLLL
+LLLLLLL.LLLLLL.LLLLLLLLLL.LLLLLLLLLLLLLLLLLLLLLLLL.LLLLLLLLLLLLLLLLL.LLLL.LLL.LLLLLLLLLLL.LLL
+.LLL..LL.L.LL.L...L.L..L...L....L.L................L....L.......L..L.....L...LLL....L....LL..
+LLLLL.LLLLLLLL.LLLLL.L.LL.LLLLLLLL.LLLLLLLLL..LLLLLLLLLLLL.LLLLLLLLL.LLLL.LLLLL.LLLLLLL.LLLLL
+LLLLLLL.LLLLLL.LLLLLLLLLL.LL.L.LLL.LLLLLL.LL.LLLLL.LLLLLLL.LLLLLLLLL.LLLL.LLL.LLLLLLLLL.LLLLL
+LLLLLLL.LLLLLL.LLLLL.LLLL.LLLLLLLLLL.L.LLLLL.LLLLLLLLLLLLLLLLLLLLLLL.LLLLLLLLLLLLLLLLLL.LLLLL
+LLLLLL..LLLLLLLLLLLLLLLLL.LLLLLLLL.L.LLL.LLL.LLLLL.LLLLLLLLLLLLLLLLL.LLLLLLLLLL.LLLLLLLLLLLLL
+LLLLLLL.LLLL.L.LLL.LLLLLLLLLLLLLLL.LLLLLLLLL.LLLLL.LLLLLLL.LLLLLLLLL.LLLL.LLLLL.LLLL.LLLLLLLL
+LLLLLLL.LLLLLLLLLLLL..LLL.LLLLLLLL..LLLLLLLLLLLLLL.LLLLLLLLLLL.LLLLLLL.LLLLLLLL.LLLLLLL.LLLLL

day11/lib.go

@@ -0,0 +1,94 @@
+package day11
+
+type Coordinate struct {
+	X, Y int
+}
+
+func GetNearbySeatStatus(coord Coordinate, checkOnlyNearby bool) int {
+	occupied := 0
+
+	for x := -1; x <= 1; x++ {
+		for y := -1; y <= 1; y++ {
+			if x == 0 && y == 0 {
+				continue
+			}
+
+			isOccupied := CheckSeatDirection(
+				coord,
+				Coordinate{X: x, Y: y},
+				checkOnlyNearby,
+			)
+
+			if isOccupied {
+				occupied++
+			}
+		}
+	}
+
+	return occupied
+}
+
+func CheckSeatDirection(coord Coordinate, dir Coordinate, checkOnlyNearby bool) bool {
+	adjCoord := Coordinate{X: coord.X + dir.X, Y: coord.Y + dir.Y}
+
+	// If out of bounds, it's not occupied and we can't check furter
+	if rows[adjCoord] == "" {
+		return false
+	}
+
+	// If we only should check one step, just check that one step
+	if checkOnlyNearby {
+		return rows[adjCoord] == "#"
+	}
+
+	// If it's a floor tile, recurse further
+	if rows[adjCoord] == "." {
+		return CheckSeatDirection(adjCoord, dir, checkOnlyNearby)
+	}
+
+	return rows[adjCoord] == "#"
+}
+
+func MakeSeatChanges(tolerance int, checkOnlyNearby bool) int {
+	changes := make(map[Coordinate]string)
+
+	// Calculate changes
+	for coord, status := range rows {
+		// Ignore floor tiles
+		if status == "." {
+			continue
+		}
+
+		// Get nearby seat statuses
+		occupiedCount := GetNearbySeatStatus(coord, checkOnlyNearby)
+
+		// If current seat is free, check that there's nobody around
+		if status == "L" && occupiedCount == 0 {
+			changes[coord] = "#"
+		}
+
+		// If the current seat isn't free, check how many people there's around
+		if status == "#" && occupiedCount >= tolerance {
+			changes[coord] = "L"
+		}
+	}
+
+	// Apply changes
+	for coord, change := range changes {
+		rows[coord] = change
+	}
+
+	return len(changes)
+}
+
+func CountOccupiedSeats() int {
+	counter := 0
+
+	for _, status := range rows {
+		if status == "#" {
+			counter++
+		}
+	}
+
+	return counter
+}

day11/parse.go

@@ -0,0 +1,21 @@
+package day11
+
+import (
+	"git.elis.nu/etu/aoc2020/utils"
+)
+
+var rows map[Coordinate]string
+
+func ParseFile(input string) {
+	rows = make(map[Coordinate]string)
+
+	x := 0
+	// Parse file
+	for _, line := range utils.GetLinesFromFile("day11/" + input + ".txt") {
+		for y := 0; y < len(line); y++ {
+			rows[Coordinate{x, y}] = string(line[y])
+		}
+
+		x++
+	}
+}

day11/solve1.go

@@ -0,0 +1,21 @@
+package day11
+
+import (
+	"log"
+)
+
+func Solve1() {
+	changes := 1
+	for changes > 0 {
+		changes = MakeSeatChanges(4, true)
+	}
+
+	log.Printf("2020-12-11.01: Answer: %d\n", CountOccupiedSeats())
+
+	// Reset input
+	for coord, status := range rows {
+		if status != "." {
+			rows[coord] = "L"
+		}
+	}
+}

day11/solve2.go

@@ -0,0 +1,14 @@
+package day11
+
+import (
+	"log"
+)
+
+func Solve2() {
+	changes := 1
+	for changes > 0 {
+		changes = MakeSeatChanges(5, false)
+	}
+
+	log.Printf("2020-12-11.02: Answer: %d\n", CountOccupiedSeats())
+}

main.go

@@ -14,6 +14,7 @@ import (
 	"git.elis.nu/etu/aoc2020/day08"
 	"git.elis.nu/etu/aoc2020/day09"
 	"git.elis.nu/etu/aoc2020/day10"
+	"git.elis.nu/etu/aoc2020/day11"
 	"git.elis.nu/etu/aoc2020/utils"
 )
 
@@ -52,5 +53,8 @@ func main() {
 
 	case "day10":
 		utils.Perf("2020-12-10", day10.ParseFile, day10.Solve1, day10.Solve2)
+
+	case "day11":
+		utils.Perf("2020-12-11", day11.ParseFile, day11.Solve1, day11.Solve2)
 	}
 }