add day-14 + benchmarks

day-14/internal/one/benchmark

@@ -0,0 +1,6 @@
+goos: linux
+goarch: amd64
+pkg: github.com/onyx-and-iris/aoc2024/day-14/internal/one
+cpu: Intel(R) Core(TM) i7-8700K CPU @ 3.70GHz
+BenchmarkSolve-12    	1000000000	         0.0007711 ns/op
+ok  	github.com/onyx-and-iris/aoc2024/day-14/internal/one	0.011s

day-14/internal/one/graph.go

@@ -0,0 +1,36 @@
+package one
+
+type dimension int
+
+type graph struct {
+	data [][]int
+}
+
+func newGraph(x, y dimension) *graph {
+	var data [][]int
+	for range y {
+		data = append(data, make([]int, x))
+	}
+
+	return &graph{data: data}
+}
+
+func (g *graph) update(robots []*robot) {
+	for _, robot := range robots {
+		g.updateEach(robot.position)
+	}
+}
+
+func (g *graph) updateEach(p position) {
+	g.data[p.y][p.x]++
+}
+
+func (g *graph) quadrant(startx, endx, starty, endy int) int {
+	var robotCount int
+	for i := starty; i < endy; i++ {
+		for j := startx; j < endx; j++ {
+			robotCount += g.data[i][j]
+		}
+	}
+	return robotCount
+}

day-14/internal/one/robot.go

@@ -0,0 +1,51 @@
+package one
+
+import (
+	"fmt"
+)
+
+type position struct {
+	x int
+	y int
+}
+
+type velocity struct {
+	x int
+	y int
+}
+
+type robot struct {
+	position position
+	velocity velocity
+}
+
+func newRobot(px, py, vx, vy int) *robot {
+	return &robot{
+		position{x: px, y: py},
+		velocity{x: vx, y: vy},
+	}
+}
+
+func (r *robot) String() string {
+	return fmt.Sprintf("position: %+v velocity: %+v", r.position, r.velocity)
+}
+
+func (r *robot) update(width, height dimension) position {
+	oldPosition := r.position
+
+	r.position.x += r.velocity.x
+	if r.position.x < 0 {
+		r.position.x = int(width) + r.position.x
+	} else if r.position.x >= int(width) {
+		r.position.x = r.position.x - int(width)
+	}
+
+	r.position.y += r.velocity.y
+	if r.position.y < 0 {
+		r.position.y = int(height) + r.position.y
+	} else if r.position.y >= int(height) {
+		r.position.y = r.position.y - int(height)
+	}
+
+	return oldPosition
+}

day-14/internal/one/solve.go

@@ -0,0 +1,41 @@
+package one
+
+import (
+	"bytes"
+)
+
+func Solve(buf []byte) (int, error) {
+	r := bytes.NewReader(buf)
+	robots, err := parseLines(r)
+	if err != nil {
+		return 0, err
+	}
+
+	const numSeconds int = 100
+	const width, height dimension = 101, 103
+
+	graph := newGraph(width, height)
+
+	for range numSeconds {
+		for _, robot := range robots {
+			robot.update(width, height)
+		}
+	}
+	graph.update(robots)
+
+	safetyFactor := 1
+	for _, v := range calculateQuadrants(graph) {
+		safetyFactor *= v
+	}
+
+	return safetyFactor, nil
+}
+
+func calculateQuadrants(graph *graph) []int {
+	topLeft := graph.quadrant(0, len(graph.data[0])/2, 0, len(graph.data)/2)
+	topRight := graph.quadrant(len(graph.data[0])/2+1, len(graph.data[0]), 0, len(graph.data)/2)
+	bottomLeft := graph.quadrant(0, len(graph.data[0])/2, len(graph.data)/2+1, len(graph.data))
+	bottomRight := graph.quadrant(len(graph.data[0])/2+1, len(graph.data[0]), len(graph.data)/2+1, len(graph.data))
+
+	return []int{topLeft, topRight, bottomLeft, bottomRight}
+}

day-14/internal/one/solve_internal_test.go

@@ -0,0 +1,15 @@
+package one
+
+import (
+	_ "embed"
+	"os"
+	"testing"
+)
+
+//go:embed testdata/input.txt
+var data []byte
+
+func BenchmarkSolve(b *testing.B) {
+	os.Stdout, _ = os.Open(os.DevNull)
+	Solve(data)
+}

day-14/internal/one/util.go

@@ -0,0 +1,40 @@
+package one
+
+import (
+	"bufio"
+	"io"
+	"regexp"
+	"strconv"
+)
+
+var reRobot = regexp.MustCompile(`p=(?P<px>\d+),(?P<py>\d+) v=(?P<vx>-?\d+),(?P<vy>-?\d+)`)
+
+func parseLines(r io.Reader) ([]*robot, error) {
+	var matches [][]string
+
+	scanner := bufio.NewScanner(r)
+	for scanner.Scan() {
+		line := scanner.Text()
+		m := reRobot.FindStringSubmatch(line)
+		matches = append(matches, m)
+	}
+
+	if err := scanner.Err(); err != nil {
+		return nil, err
+	}
+
+	var robots []*robot
+	for _, m := range matches {
+		robots = append(robots, newRobot(mustConv(m[1]), mustConv(m[2]), mustConv(m[3]), mustConv(m[4])))
+	}
+
+	return robots, nil
+}
+
+func mustConv(s string) int {
+	n, err := strconv.Atoi(s)
+	if err != nil {
+		panic(err)
+	}
+	return n
+}