Day 15 part 2 done.

2 files changed, 145 insertions, 10 deletions

diff --git a/2024/go/input/day15_3.test b/2024/go/input/day15_3.test
new file mode 100644
index 0000000..6ee6098
--- /dev/null
+++ b/2024/go/input/day15_3.test
@@ -0,0 +1,9 @@
+#######
+#...#.#
+#.....#
+#..OO@#
+#..O..#
+#.....#
+#######
+
+<vv<<^^<<^^
diff --git a/2024/go/src/day15/main.go b/2024/go/src/day15/main.go
index becf95f..684f045 100644
--- a/2024/go/src/day15/main.go
+++ b/2024/go/src/day15/main.go
@@ -3,6 +3,7 @@ package main
 import (
 	"fmt"
 	"os"
+	"slices"
 	"strings"
 )
 
@@ -71,13 +72,37 @@ func inBounds(x, y, w, h int) bool {
 }
 
 func isBlock(x, y int, warehouse Grid) bool {
-	return warehouse[x][y] == 'O'
+	return slices.Contains([]byte{'O', '[', ']'}, warehouse[x][y])
 }
 
 func isWall(x, y int, warehouse Grid) bool {
 	return warehouse[x][y] == '#'
 }
 
+func constructWideWarehouse(warehouse Grid) Grid {
+	var newWarehouse Grid
+	for i := 0; i < len(warehouse); i++ {
+		var row []byte
+		for j := 0; j < len(warehouse[0]); j++ {
+			if warehouse[i][j] == '.' {
+				row = append(row, '.')
+				row = append(row, '.')
+			} else if warehouse[i][j] == 'O' {
+				row = append(row, '[')
+				row = append(row, ']')
+			} else if warehouse[i][j] == '@' {
+				row = append(row, '@')
+				row = append(row, '.')
+			} else {
+				row = append(row, '#')
+				row = append(row, '#')
+			}
+		}
+		newWarehouse = append(newWarehouse, row)
+	}
+	return newWarehouse
+}
+
 func simulate(input Input) Grid {
 	dirMap := map[byte]Point{
 		'<': {0, -1},
@@ -103,6 +128,7 @@ func simulate(input Input) Grid {
 				}
 				if !isWall(nx+dx*step, ny+dy*step, input.warehouse) {
 					for i := step; i >= 1; i-- {
+						// swaps blocks backwares
 						input.warehouse[nx+dx*(i-1)][ny+dy*(i-1)], input.warehouse[nx+dx*(i)][ny+dy*(i)] = input.warehouse[nx+dx*(i)][ny+dy*(i)], input.warehouse[nx+dx*(i-1)][ny+dy*(i-1)]
 					}
 					input.warehouse[nx][ny], input.warehouse[robotPos.x][robotPos.y] = input.warehouse[robotPos.x][robotPos.y], input.warehouse[nx][ny]
@@ -115,11 +141,110 @@ func simulate(input Input) Grid {
 	return input.warehouse
 }
 
+func getBlocksToMove(pos Point, dir byte, blocksToMove *map[Point]bool, warehosue Grid) {
+	dirMap := map[byte]Point{
+		'<': {0, -1},
+		'>': {0, 1},
+		'^': {-1, 0},
+		'v': {1, 0},
+	}
+	x, y := pos.x, pos.y
+	(*blocksToMove)[pos] = true
+	dx, dy := dirMap[dir].x, dirMap[dir].y
+	if warehosue[x][y] == '[' {
+		if !(*blocksToMove)[Point{x, y + 1}] {
+			getBlocksToMove(Point{x, y + 1}, dir, blocksToMove, warehosue)
+		}
+		if isBlock(x+dx, y+dy, warehosue) {
+			getBlocksToMove(Point{x + dx, y + dy}, dir, blocksToMove, warehosue)
+		}
+	} else if warehosue[x][y] == ']' {
+		if !(*blocksToMove)[Point{x, y - 1}] {
+			getBlocksToMove(Point{x, y - 1}, dir, blocksToMove, warehosue)
+		}
+		if isBlock(x+dx, y+dy, warehosue) {
+			getBlocksToMove(Point{x + dx, y + dy}, dir, blocksToMove, warehosue)
+		}
+	}
+
+}
+
+func copySlice(src [][]byte) [][]byte {
+	dest := make([][]byte, len(src))
+	for i, inner := range src {
+		if inner != nil {
+			dest[i] = make([]byte, len(inner))
+			copy(dest[i], inner)
+		}
+	}
+	return dest
+}
+
+func canMove(blocksToMove map[Point]bool, delta Point, warehouse Grid) bool {
+	for b := range blocksToMove {
+		x, y := b.x, b.y
+		nx, ny := x+delta.x, y+delta.y
+		if isWall(nx, ny, warehouse) {
+			return false
+		}
+	}
+	return true
+}
+
+func simulateWide(input Input) Grid {
+	dirMap := map[byte]Point{
+		'<': {0, -1},
+		'>': {0, 1},
+		'^': {-1, 0},
+		'v': {1, 0},
+	}
+	w, h := len(input.warehouse), len(input.warehouse[0])
+	robotPos := getRobotsPos(input.warehouse)
+	for _, dir := range input.directions {
+		dx, dy := dirMap[dir].x, dirMap[dir].y
+		nx, ny := robotPos.x+dx, robotPos.y+dy
+		// fmt.Printf("dir: %v\n", string(dir))
+		// printGrid(input.warehouse)
+		// fmt.Println()
+		if inBounds(nx, ny, w, h) && !isWall(nx, ny, input.warehouse) {
+			if input.warehouse[nx][ny] == '.' {
+				input.warehouse[nx][ny], input.warehouse[robotPos.x][robotPos.y] = input.warehouse[robotPos.x][robotPos.y], input.warehouse[nx][ny]
+				robotPos.x = nx
+				robotPos.y = ny
+			} else if isBlock(nx, ny, input.warehouse) {
+				blocksToMove := make(map[Point]bool)
+				if isBlock(nx, ny, input.warehouse) {
+					getBlocksToMove(Point{nx, ny}, dir, &blocksToMove, input.warehouse)
+					if canMove(blocksToMove, dirMap[dir], input.warehouse) {
+						copiedWarehouse := copySlice(input.warehouse)
+						for b := range blocksToMove {
+							copiedWarehouse[b.x][b.y] = '.'
+						}
+						for b := range blocksToMove {
+							copiedWarehouse[b.x+dx][b.y+dy] = input.warehouse[b.x][b.y]
+						}
+						input.warehouse = copiedWarehouse
+						for p := range blocksToMove {
+							delete(blocksToMove, p)
+						}
+						input.warehouse[nx][ny] = input.warehouse[robotPos.x][robotPos.y]
+						input.warehouse[robotPos.x][robotPos.y] = '.'
+						robotPos.x = nx
+						robotPos.y = ny
+
+					}
+				}
+			}
+		}
+	}
+	return input.warehouse
+}
+
 func sumGpsCoordinates(warehouse Grid) int {
 	ans := 0
 	for i, row := range warehouse {
 		for j, cell := range row {
-			if cell == 'O' {
+			if cell == 'O' || cell == '[' {
 				ans += i*100 + j
 			}
 		}
@@ -129,15 +254,16 @@ func sumGpsCoordinates(warehouse Grid) int {
 
 func solve_part_one(data string) int {
 	input := parseInput(data)
-	// printGrid(input.warehouse)
-	// printDirs(input.directions)
-	// fmt.Println()
-	warehosue := simulate(input)
-	return sumGpsCoordinates(warehosue)
+	warehouse := simulate(input)
+	return sumGpsCoordinates(warehouse)
 }
 
 func solve_part_two(data string) int {
-	return 42
+	input := parseInput(data)
+	warehouse := constructWideWarehouse(input.warehouse)
+	input.warehouse = warehouse
+	simualtedWareHouse := simulateWide(input)
+	return sumGpsCoordinates(simualtedWareHouse)
 }
 
 func main() {
@@ -145,6 +271,6 @@ func main() {
 	prod := FileRead("../input/day15.prod")
 	fmt.Println("Part_1 test: ", solve_part_one(test))
 	fmt.Println("Part_1 prod: ", solve_part_one(prod))
-	// fmt.Println("Part_2 test: ", solve_part_two(test))
-	// fmt.Println("Part_2 prod: ", solve_part_two(test))
+	fmt.Println("Part_2 test: ", solve_part_two(test))
+	fmt.Println("Part_2 prod: ", solve_part_two(prod))
 }