2024 day 14

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dbut2 · Dec 14, 2024 · fab63ac · fab63ac
1 parent 38ff547
commit fab63ac
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Showing 4 changed files with 147 additions and 0 deletions.
diff --git a/2024/14/1.go b/2024/14/1.go
@@ -0,0 +1,64 @@
+package main
+
+import (
+	"github.com/dbut2/advent-of-code/pkg/harness"
+)
+
+func solve(input [][]int) int {
+	type robot struct {
+		x, y   int
+		dx, dy int
+	}
+
+	var rs []robot
+	for _, line := range input {
+		rs = append(rs, robot{
+			x:  line[0],
+			y:  line[1],
+			dx: line[2],
+			dy: line[3],
+		})
+	}
+
+	width := 0
+	height := 0
+	for _, r := range rs {
+		width = max(width, r.x+1)
+		height = max(height, r.y+1)
+	}
+
+	for range 100 {
+		for i := range rs {
+			rs[i].x = (rs[i].x + rs[i].dx + width) % width
+			rs[i].y = (rs[i].y + rs[i].dy + height) % height
+		}
+	}
+
+	quads := [4]int{}
+	for _, r := range rs {
+		left := r.x < width/2
+		right := r.x > width/2
+
+		up := r.y < height/2
+		down := r.y > height/2
+
+		switch {
+		case left && up:
+			quads[0]++
+		case left && down:
+			quads[1]++
+		case right && up:
+			quads[2]++
+		case right && down:
+			quads[3]++
+		}
+	}
+
+	return quads[0] * quads[1] * quads[2] * quads[3]
+}
+
+func main() {
+	h := harness.New(solve)
+	h.Expect(1, 12)
+	h.Run()
+}
diff --git a/2024/14/2.go b/2024/14/2.go
@@ -0,0 +1,71 @@
+package main
+
+import (
+	"github.com/dbut2/advent-of-code/pkg/harness"
+	"github.com/dbut2/advent-of-code/pkg/sets"
+)
+
+func solve(input [][]int) int {
+	type robot struct {
+		x, y   int
+		dx, dy int
+	}
+
+	var rs []robot
+	for _, line := range input {
+		rs = append(rs, robot{
+			x:  line[0],
+			y:  line[1],
+			dx: line[2],
+			dy: line[3],
+		})
+	}
+
+	width := 0
+	height := 0
+	for _, r := range rs {
+		width = max(width, r.x+1)
+		height = max(height, r.y+1)
+	}
+
+	c := 0
+	for {
+		c++
+		tiles := sets.Set[[2]int]{}
+		for i := range rs {
+			r := rs[i]
+			r.x = (r.x + r.dx + width) % width
+			r.y = (r.y + r.dy + height) % height
+			rs[i] = r
+			tiles.Add([2]int{r.x, r.y})
+		}
+
+		// Check grid for any 3x3 filled in square, assuming to be a tree
+		hasSquare := false
+		for x := range width - 3 {
+			for y := range height - 3 {
+				thisHas := true
+				for dx := range 3 {
+					for dy := range 3 {
+						if !tiles.Contains([2]int{x + dx, y + dy}) {
+							thisHas = false
+							break
+						}
+					}
+				}
+				if thisHas {
+					hasSquare = true
+				}
+			}
+		}
+		if hasSquare {
+			break
+		}
+	}
+	return c
+}
+
+func main() {
+	h := harness.New(solve)
+	h.Run()
+}
diff --git a/2024/14/test1.txt b/2024/14/test1.txt
@@ -0,0 +1,12 @@
+p=0,4 v=3,-3
+p=6,3 v=-1,-3
+p=10,3 v=-1,2
+p=2,0 v=2,-1
+p=0,0 v=1,3
+p=3,0 v=-2,-2
+p=7,6 v=-1,-3
+p=3,0 v=-1,-2
+p=9,3 v=2,3
+p=7,3 v=-1,2
+p=2,4 v=2,-3
+p=9,5 v=-3,-3
diff --git a/2024/14/test2.txt b/2024/14/test2.txt