feat(2024): add day 15 part 1 and start of part 2

Author: believer

go/2024/puzzles/day15/main.go

@@ -0,0 +1,116 @@
+package main
+
+import (
+	"fmt"
+	"strings"
+
+	"github.com/believer/aoc-2024/utils/files"
+	"github.com/believer/aoc-2024/utils/grid"
+)
+
+func main() {
+	fmt.Println("Part 1: ", part1("input.txt"))
+	fmt.Println("Part 2: ", part2("input.txt"))
+}
+
+func part1(name string) int {
+	p := files.ReadParagraphs(name)
+	warehouse := grid.New(p[0])
+	moves := []grid.Point{}
+	gps := 0
+
+	// Get all moves from list
+	for _, moveLine := range p[1] {
+		for _, m := range strings.Split(moveLine, "") {
+			switch m {
+			case "<":
+				moves = append(moves, grid.LEFT)
+			case "^":
+				moves = append(moves, grid.UP)
+			case ">":
+				moves = append(moves, grid.RIGHT)
+			case "v":
+				moves = append(moves, grid.DOWN)
+			}
+		}
+	}
+
+	// Find robot start position
+	robot := warehouse.Find('@')
+
+	for _, m := range moves {
+		next := robot.Add(m)
+
+		// Move into wall, do nothing
+		if warehouse.Get(next) == '#' {
+			continue
+		}
+
+		// Moving a box. Find last location that's not a
+		// box and move our box there
+		if warehouse.Get(next) == 'O' {
+			tmp := next.Add(m)
+
+			for {
+				if warehouse.Get(tmp) != 'O' {
+					break
+				}
+
+				tmp = tmp.Add(m)
+			}
+
+			// Don't move boxes into wall
+			if warehouse.Get(tmp) == '#' {
+				continue
+			}
+
+			warehouse.Update(tmp, 'O')
+		}
+
+		// Update robot position
+		warehouse.Update(next, '@')
+		warehouse.Update(robot, '.')
+		robot = next
+	}
+
+	for _, box := range warehouse.FindAll('O') {
+		gps += 100*box.Y + box.X
+	}
+
+	return gps
+}
+
+func part2(name string) int {
+	p := files.ReadParagraphs(name)
+	warehouse := grid.New(p[0])
+	doubleWarehouse := grid.FromSize(warehouse.Width*2, warehouse.Height)
+	gps := 0
+
+	// Scale warehouse
+	for y := range warehouse.Height {
+		for x := range warehouse.Width {
+			wp := grid.Point{X: x, Y: y}
+			p := grid.Point{X: x * 2, Y: y}
+			p2 := grid.Point{X: x*2 + 1, Y: y}
+
+			switch warehouse.Get(wp) {
+			case '.':
+				doubleWarehouse.Update(p, '.')
+				doubleWarehouse.Update(p2, '.')
+			case '#':
+				doubleWarehouse.Update(p, '#')
+				doubleWarehouse.Update(p2, '#')
+			case 'O':
+				doubleWarehouse.Update(p, '[')
+				doubleWarehouse.Update(p2, ']')
+			case '@':
+				doubleWarehouse.Update(p, '@')
+				doubleWarehouse.Update(p2, '.')
+			}
+		}
+	}
+
+	doubleWarehouse.Debug()
+
+	return gps
+}

go/2024/puzzles/day15/main_test.go

@@ -0,0 +1,43 @@
+package main
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestPart1(t *testing.T) {
+	t.Run("Part 1", func(t *testing.T) {
+		expected := 10092
+		actual := part1("test-input.txt")
+		assert.Equal(t, expected, actual)
+	})
+}
+
+func TestPart1Small(t *testing.T) {
+	t.Run("Part 1", func(t *testing.T) {
+		expected := 2028
+		actual := part1("test-input-small.txt")
+		assert.Equal(t, expected, actual)
+	})
+}
+
+func TestPart2(t *testing.T) {
+	t.Run("Part 2", func(t *testing.T) {
+		expected := 0
+		actual := part2("test-input.txt")
+		assert.Equal(t, expected, actual)
+	})
+}
+
+func BenchmarkPart1(b *testing.B) {
+	for i := 0; i < b.N; i++ {
+		part1("input.txt")
+	}
+}
+
+func BenchmarkPart2(b *testing.B) {
+	for i := 0; i < b.N; i++ {
+		part2("input.txt")
+	}
+}

go/2024/puzzles/day15/test-input-small.txt

@@ -0,0 +1,10 @@
+########
+#..O.O.#
+##@.O..#
+#...O..#
+#.#.O..#
+#...O..#
+#......#
+########
+
+<^^>>>vv<v>>v<<

go/2024/puzzles/day15/test-input.txt

@@ -0,0 +1,21 @@
+##########
+#..O..O.O#
+#......O.#
+#.OO..O.O#
+#..O@..O.#
+#O#..O...#
+#O..O..O.#
+#.OO.O.OO#
+#....O...#
+##########
+
+<vv>^<v^>v>^vv^v>v<>v^v<v<^vv<<<^><<><>>v<vvv<>^v^>^<<<><<v<<<v^vv^v>^
+vvv<<^>^v^^><<>>><>^<<><^vv^^<>vvv<>><^^v>^>vv<>v<<<<v<^v>^<^^>>>^<v<v
+><>vv>v^v^<>><>>>><^^>vv>v<^^^>>v^v^<^^>v^^>v^<^v>v<>>v^v^<v>v^^<^^vv<
+<<v<^>>^^^^>>>v^<>vvv^><v<<<>^^^vv^<vvv>^>v<^^^^v<>^>vvvv><>>v^<<^^^^^
+^><^><>>><>^^<<^^v>>><^<v>^<vv>>v>>>^v><>^v><<<<v>>v<v<v>vvv>^<><<>^><
+^>><>^v<><^vvv<^^<><v<<<<<><^v<<<><<<^^<v<^^^><^>>^<v^><<<^>>^v<v^v<v^
+>^>>^v>vv>^<<^v<>><<><<v<<v><>v<^vv<<<>^^v^>^^>>><<^v>>v^v><^^>>^<>vv^
+<><^^>^^^<><vvvvv^v<v<<>^v<v>v<<^><<><<><<<^^<<<^<<>><<><^^^>^^<>^>v<>
+^^>vv<^v^v<vv>^<><v<^v>^^^>>>^^vvv^>vvv<>>>^<^>>>>>^<<^v>^vvv<>^<><<v>
+v^^>>><<^^<>>^v^<v^vv<>v^<<>^<^v^v><^<<<><<^<v><v<>vv>>v><v^<vv<>v^<<^