Added day 14

2024/cmd/root.go

@@ -22,6 +22,7 @@ import (
 	"cpatino.com/advent-of-code/2024/day11"
 	"cpatino.com/advent-of-code/2024/day12"
 	"cpatino.com/advent-of-code/2024/day13"
+	"cpatino.com/advent-of-code/2024/day14"
 )
 
 var days = map[int]func(string) (int, int){
@@ -38,6 +39,7 @@ var days = map[int]func(string) (int, int){
 	11: day11.Run,
 	12: day12.Run,
 	13: day13.Run,
+	14: day14.Run,
 }
 
 var rootCmd = &cobra.Command{

2024/day14/day14.go

@@ -0,0 +1,162 @@
+package day14
+
+import (
+	"bufio"
+	"fmt"
+	"image"
+	"math"
+	"os"
+	"regexp"
+	"strconv"
+)
+
+type Robot struct {
+	p image.Point
+	v image.Point
+}
+
+func deepcopyRobots(robots []Robot) []Robot {
+	newRobots := make([]Robot, len(robots))
+	for step, robot := range robots {
+		newRobots[step] = Robot{p: robot.p, v: robot.v}
+	}
+
+	return newRobots
+}
+
+func printField(robots []Robot, xMax, yMax int) {
+	counts := make(map[image.Point]int)
+	for _, robot := range robots {
+		counts[robot.p]++
+	}
+
+	for j := 0; j < yMax; j++ {
+		for i := 0; i < xMax; i++ {
+			if count, ok := counts[image.Pt(i, j)]; !ok {
+				fmt.Print(" ")
+			} else {
+				fmt.Print(count)
+			}
+		}
+		fmt.Println()
+	}
+}
+
+func moveRobots(robots []Robot, xMax, yMax int) {
+	rect := image.Rect(0, 0, xMax, yMax)
+
+	for i := range robots {
+		robot := &robots[i]
+
+		robot.p = robot.p.Add(robot.v)
+		robot.p = robot.p.Mod(rect)
+	}
+}
+
+func calculateSafety(robots []Robot, xMax, yMax int) int {
+	quadrants := []int{0, 0, 0, 0}
+
+	middleX := xMax / 2
+	middleY := yMax / 2
+
+	bounds := []image.Rectangle{
+		image.Rect(0, 0, middleX, middleY),
+		image.Rect(middleX, 0, xMax, middleY),
+		image.Rect(0, middleY, middleX, yMax),
+		image.Rect(middleX, middleY, xMax, yMax),
+	}
+
+	for _, robot := range robots {
+		if robot.p.X == middleX || robot.p.Y == middleY {
+			continue
+		}
+
+		for i, bound := range bounds {
+			if robot.p.In(bound) {
+				quadrants[i]++
+				break
+			}
+		}
+	}
+
+	safety := 1
+	for _, quad := range quadrants {
+		safety *= quad
+	}
+
+	return safety
+}
+
+func calculateSTD(robots []Robot) float64 {
+	numRobots := len(robots)
+
+	var sum image.Point
+
+	for _, robot := range robots {
+		sum.X += robot.p.X
+		sum.Y += robot.p.Y
+	}
+
+	xMean := float64(sum.X) / float64(numRobots)
+	yMean := float64(sum.Y) / float64(numRobots)
+
+	var variance float64
+	for _, robot := range robots {
+		dx := float64(robot.p.X) - xMean
+		dy := float64(robot.p.Y) - yMean
+		variance += dx*dx + dy*dy
+	}
+
+	return math.Sqrt(variance / float64(numRobots))
+}
+
+func Part1(robots []Robot, xMax, yMax int) int {
+	for step := 0; step < 100; step++ {
+		moveRobots(robots, xMax, yMax)
+	}
+
+	return calculateSafety(robots, xMax, yMax)
+}
+
+func Part2(robots []Robot, xMax, yMax int) int {
+	for step := 0; true; step++ {
+		moveRobots(robots, xMax, yMax)
+
+		std := calculateSTD(robots)
+		if std < 30 {
+			return step + 1
+		}
+	}
+
+	return -1
+}
+
+func Run(filename string) (int, int) {
+	file, err := os.Open(filename)
+	if err != nil {
+		panic(err)
+	}
+	defer file.Close()
+
+	var robots []Robot
+	regex := regexp.MustCompile(`p=(-?\d+),(-?\d+) v=(-?\d+),(-?\d+)`)
+
+	scanner := bufio.NewScanner(file)
+	for scanner.Scan() {
+		fields := make([]int, 4)
+		for i, match := range regex.FindStringSubmatch(scanner.Text())[1:] {
+			fields[i], _ = strconv.Atoi(match)
+		}
+
+		robots = append(robots, Robot{p: image.Pt(fields[0], fields[1]), v: image.Pt(fields[2], fields[3])})
+	}
+
+	if err := scanner.Err(); err != nil {
+		panic(err)
+	}
+
+	part1 := Part1(deepcopyRobots(robots), 101, 103)
+	part2 := Part2(deepcopyRobots(robots), 101, 103)
+
+	return part1, part2
+}

2024/day14/day14_test.go

@@ -0,0 +1,39 @@
+package day14
+
+import (
+	"os"
+	"testing"
+)
+
+func TestDay14(t *testing.T) {
+	filename := "test.txt"
+	if _, err := os.Stat(filename); os.IsNotExist(err) {
+		t.Fatalf("test file does not exist: %v", filename)
+	}
+
+	part1, _ := Run(filename)
+
+	expectedPart1 := 21
+	if part1 != expectedPart1 {
+		t.Fatalf("unexpected part1:\nwant:\t%d\ngot:\t%d", expectedPart1, part1)
+	}
+}
+
+func TestDay14Solutions(t *testing.T) {
+	filename := "input.txt"
+	if _, err := os.Stat(filename); os.IsNotExist(err) {
+		t.Fatalf("test file does not exist: %v", filename)
+	}
+
+	part1, part2 := Run(filename)
+
+	expectedPart1 := 211692000
+	if part1 != expectedPart1 {
+		t.Fatalf("unexpected part1:\nwant:\t%d\ngot:\t%d", expectedPart1, part1)
+	}
+
+	expectedPart2 := 6587
+	if part2 != expectedPart2 {
+		t.Fatalf("unexpected part2:\nwant:\t%d\ngot:\t%d", expectedPart2, part2)
+	}
+}

2024/day14/input.txt

@@ -0,0 +1,500 @@
+p=8,15 v=12,-27
+p=58,24 v=91,-30
+p=63,33 v=-60,-5
+p=41,53 v=42,79
+p=84,100 v=-15,7
+p=19,45 v=-17,-25
+p=49,46 v=14,57
+p=46,5 v=-73,-32
+p=66,41 v=18,56
+p=83,61 v=18,-63
+p=53,26 v=-14,37
+p=40,73 v=51,2
+p=0,70 v=81,-16
+p=93,9 v=44,91
+p=48,18 v=-94,61
+p=70,96 v=-65,-15
+p=22,16 v=23,-41
+p=92,18 v=55,96
+p=72,95 v=91,92
+p=31,47 v=5,-47
+p=74,39 v=-88,57
+p=30,99 v=28,-36
+p=18,23 v=61,-73
+p=58,40 v=-60,-65
+p=66,3 v=18,13
+p=89,52 v=-59,-39
+p=73,99 v=32,66
+p=50,48 v=37,37
+p=90,74 v=95,-40
+p=28,68 v=38,-64
+p=91,19 v=-84,91
+p=26,6 v=-35,-38
+p=71,22 v=-6,-90
+p=2,2 v=66,-35
+p=86,15 v=-66,-52
+p=48,19 v=-68,91
+p=78,47 v=-73,-51
+p=23,88 v=-13,-18
+p=94,77 v=-11,-38
+p=35,23 v=-96,30
+p=0,85 v=67,-98
+p=89,95 v=-31,-70
+p=67,43 v=-97,36
+p=95,36 v=4,65
+p=11,70 v=-57,-99
+p=4,40 v=9,-67
+p=66,95 v=-51,-55
+p=25,47 v=11,-27
+p=98,26 v=-29,-66
+p=14,49 v=-56,-8
+p=97,52 v=-99,60
+p=100,57 v=76,60
+p=64,6 v=-5,-52
+p=43,12 v=-46,-34
+p=8,66 v=37,-22
+p=2,47 v=76,-3
+p=83,22 v=-56,53
+p=57,98 v=-10,-20
+p=84,59 v=-19,-81
+p=55,58 v=-78,-44
+p=32,45 v=56,39
+p=33,95 v=93,47
+p=21,39 v=-49,-67
+p=71,82 v=73,-96
+p=46,23 v=51,-80
+p=73,93 v=91,46
+p=90,40 v=-80,35
+p=22,62 v=35,-90
+p=28,36 v=98,9
+p=95,3 v=12,70
+p=75,0 v=68,-56
+p=1,96 v=68,-18
+p=64,62 v=-14,-21
+p=2,14 v=12,16
+p=11,51 v=-11,-71
+p=4,33 v=-91,64
+p=1,77 v=-34,2
+p=72,70 v=-51,63
+p=75,10 v=-48,-18
+p=67,98 v=-65,-13
+p=57,14 v=78,12
+p=51,47 v=23,-85
+p=97,78 v=-92,-51
+p=85,65 v=-43,-63
+p=30,30 v=29,-24
+p=30,22 v=93,32
+p=6,78 v=-62,-16
+p=26,91 v=47,46
+p=16,15 v=29,-10
+p=64,40 v=62,-74
+p=55,74 v=42,-36
+p=95,6 v=12,90
+p=8,25 v=-39,-28
+p=54,72 v=78,-18
+p=22,63 v=95,1
+p=26,54 v=43,38
+p=41,62 v=-20,83
+p=98,56 v=21,-86
+p=82,94 v=31,88
+p=97,102 v=-15,-16
+p=15,76 v=53,1
+p=88,88 v=7,-54
+p=66,3 v=-42,-73
+p=77,83 v=-98,-34
+p=69,74 v=-74,-80
+p=50,66 v=-87,43
+p=24,68 v=-58,20
+p=29,26 v=6,-90
+p=36,62 v=-25,-78
+p=96,94 v=40,-73
+p=25,16 v=75,-83
+p=55,50 v=59,40
+p=8,62 v=83,-82
+p=89,30 v=-74,86
+p=49,67 v=-80,-82
+p=63,71 v=-41,41
+p=67,27 v=-42,99
+p=77,99 v=77,70
+p=59,89 v=69,66
+p=0,21 v=21,93
+p=13,54 v=20,59
+p=88,24 v=-43,32
+p=54,2 v=78,8
+p=32,28 v=24,-45
+p=87,42 v=-84,38
+p=94,28 v=-22,-38
+p=20,7 v=-71,81
+p=92,78 v=-29,-79
+p=36,41 v=-59,57
+p=75,97 v=3,-56
+p=76,102 v=-30,84
+p=6,92 v=-26,49
+p=75,0 v=-95,7
+p=9,94 v=94,-95
+p=45,45 v=8,46
+p=32,6 v=66,-92
+p=38,86 v=-82,-99
+p=31,36 v=-12,33
+p=6,15 v=4,81
+p=11,58 v=39,81
+p=41,81 v=-13,85
+p=3,20 v=-15,3
+p=20,66 v=-7,-85
+p=29,87 v=-51,-72
+p=83,65 v=-4,-33
+p=0,79 v=39,85
+p=4,94 v=7,-98
+p=88,97 v=-66,89
+p=92,61 v=58,80
+p=63,65 v=32,40
+p=16,82 v=-53,-20
+p=57,57 v=55,-63
+p=13,0 v=-30,24
+p=55,23 v=46,-48
+p=11,69 v=57,-41
+p=17,26 v=34,-8
+p=10,58 v=-21,-61
+p=30,45 v=15,38
+p=36,5 v=74,-56
+p=45,37 v=83,14
+p=14,65 v=64,90
+p=40,99 v=74,-50
+p=46,46 v=-69,-89
+p=39,89 v=97,-17
+p=27,92 v=24,85
+p=16,21 v=-71,92
+p=77,102 v=-47,-53
+p=60,84 v=87,32
+p=98,49 v=97,-70
+p=58,65 v=18,-17
+p=69,86 v=18,-79
+p=67,64 v=-65,-3
+p=34,102 v=-91,-16
+p=100,81 v=35,23
+p=55,11 v=-42,11
+p=34,82 v=-68,25
+p=42,49 v=-46,37
+p=68,101 v=-60,89
+p=57,25 v=64,-70
+p=36,28 v=97,-28
+p=83,5 v=41,51
+p=22,4 v=73,61
+p=45,69 v=-53,-73
+p=32,58 v=-13,64
+p=87,94 v=-61,90
+p=46,76 v=97,-3
+p=1,89 v=7,-97
+p=42,6 v=-99,-17
+p=23,99 v=-81,-34
+p=15,33 v=19,-27
+p=86,33 v=93,-56
+p=77,31 v=-44,-83
+p=91,5 v=95,9
+p=0,1 v=11,52
+p=70,5 v=-84,-53
+p=43,91 v=32,-57
+p=48,47 v=-72,24
+p=37,26 v=47,-50
+p=64,81 v=-47,23
+p=21,82 v=33,1
+p=94,71 v=-30,43
+p=74,85 v=-24,-57
+p=78,93 v=-84,-16
+p=27,82 v=-17,-36
+p=22,78 v=-49,41
+p=5,89 v=42,-13
+p=54,41 v=-46,15
+p=92,13 v=-16,-48
+p=35,97 v=-77,-93
+p=100,42 v=-11,77
+p=86,96 v=56,37
+p=11,48 v=70,-49
+p=71,78 v=35,68
+p=15,53 v=53,-16
+p=29,99 v=93,-77
+p=66,0 v=-19,69
+p=46,77 v=91,-23
+p=5,37 v=7,17
+p=63,50 v=87,-44
+p=87,24 v=-71,-11
+p=86,93 v=53,90
+p=74,99 v=68,-12
+p=3,85 v=-58,-78
+p=72,25 v=84,75
+p=90,44 v=90,-45
+p=61,46 v=73,-5
+p=83,10 v=-67,-21
+p=63,53 v=-14,-67
+p=86,37 v=-84,79
+p=98,68 v=90,2
+p=60,55 v=45,-81
+p=68,99 v=82,26
+p=82,82 v=-15,-63
+p=59,30 v=65,18
+p=39,44 v=-64,70
+p=27,102 v=37,-27
+p=79,37 v=4,74
+p=97,76 v=-46,-52
+p=33,87 v=-65,87
+p=61,8 v=-57,-24
+p=36,67 v=-82,-42
+p=79,8 v=45,8
+p=89,82 v=-52,65
+p=47,20 v=-11,-79
+p=75,31 v=12,64
+p=41,5 v=19,-53
+p=26,31 v=-82,38
+p=23,72 v=-3,43
+p=12,42 v=-31,6
+p=63,21 v=-52,-58
+p=78,42 v=22,-28
+p=91,26 v=-20,94
+p=45,36 v=-19,-59
+p=35,24 v=33,13
+p=97,18 v=90,-10
+p=36,25 v=13,-34
+p=51,101 v=60,8
+p=91,30 v=-72,27
+p=11,44 v=-57,-68
+p=42,11 v=24,66
+p=47,101 v=-32,-95
+p=55,18 v=-69,-71
+p=55,76 v=46,43
+p=86,1 v=53,27
+p=11,52 v=-66,-5
+p=94,78 v=-43,-17
+p=49,24 v=79,-9
+p=97,0 v=12,48
+p=62,72 v=89,8
+p=30,41 v=84,-67
+p=97,40 v=2,-23
+p=59,7 v=91,-48
+p=54,56 v=-64,60
+p=41,61 v=-18,-2
+p=27,40 v=-21,17
+p=14,97 v=76,-11
+p=12,48 v=-99,98
+p=24,67 v=66,-41
+p=84,63 v=-52,62
+p=37,3 v=28,8
+p=18,11 v=-44,7
+p=100,49 v=-39,-64
+p=6,36 v=56,-73
+p=30,91 v=-50,12
+p=47,60 v=-75,-32
+p=68,38 v=-5,-87
+p=3,75 v=-93,-49
+p=68,53 v=42,37
+p=68,2 v=50,10
+p=7,7 v=52,31
+p=70,71 v=-30,-52
+p=50,77 v=-19,-14
+p=34,38 v=20,-69
+p=5,89 v=71,1
+p=18,77 v=18,78
+p=26,30 v=56,-70
+p=91,99 v=-62,-94
+p=32,15 v=83,-10
+p=78,71 v=-47,19
+p=23,98 v=-17,70
+p=87,52 v=-8,-92
+p=77,74 v=-88,26
+p=84,3 v=-20,-21
+p=72,25 v=-56,-89
+p=63,25 v=60,33
+p=19,69 v=75,63
+p=91,10 v=63,48
+p=9,54 v=-25,-97
+p=12,79 v=89,-39
+p=30,57 v=-77,-43
+p=60,12 v=-73,-72
+p=79,7 v=-77,42
+p=41,82 v=41,56
+p=91,76 v=-66,66
+p=37,80 v=60,-14
+p=60,16 v=-23,10
+p=33,69 v=97,25
+p=52,75 v=-15,48
+p=93,94 v=-21,-85
+p=77,88 v=-29,-33
+p=32,6 v=-94,-59
+p=51,30 v=-78,-90
+p=66,100 v=-74,-34
+p=2,12 v=-52,-11
+p=9,11 v=90,94
+p=83,13 v=-61,-10
+p=16,80 v=98,-38
+p=72,13 v=-24,10
+p=40,67 v=-19,-25
+p=33,4 v=-1,-26
+p=44,87 v=-53,65
+p=85,98 v=35,-31
+p=31,45 v=1,-65
+p=28,17 v=56,63
+p=78,9 v=-93,-82
+p=6,37 v=-57,-93
+p=93,53 v=-34,75
+p=100,1 v=7,9
+p=55,32 v=69,96
+p=13,74 v=-44,25
+p=80,65 v=30,-29
+p=40,37 v=51,97
+p=21,53 v=36,-8
+p=52,97 v=-41,-93
+p=15,98 v=-44,-15
+p=37,95 v=10,-97
+p=95,23 v=-29,-71
+p=33,97 v=20,10
+p=46,15 v=-96,92
+p=14,70 v=89,-20
+p=74,82 v=-12,48
+p=7,65 v=20,-8
+p=84,13 v=-48,74
+p=68,51 v=-5,38
+p=36,67 v=47,-62
+p=11,95 v=57,-14
+p=47,28 v=-59,-91
+p=38,53 v=-4,63
+p=61,96 v=85,3
+p=68,58 v=73,-21
+p=75,64 v=87,83
+p=63,83 v=82,-78
+p=58,78 v=64,-38
+p=38,7 v=-27,-95
+p=24,68 v=66,-21
+p=61,72 v=32,-81
+p=20,33 v=11,-89
+p=86,53 v=-69,98
+p=13,9 v=-74,-84
+p=80,46 v=-52,-46
+p=30,26 v=1,-49
+p=38,56 v=19,62
+p=80,71 v=-66,19
+p=65,65 v=64,-1
+p=38,36 v=-77,-5
+p=80,46 v=-68,-32
+p=35,31 v=-82,13
+p=45,27 v=70,-6
+p=4,86 v=-39,45
+p=64,50 v=73,79
+p=71,61 v=13,22
+p=77,59 v=81,23
+p=10,29 v=25,54
+p=100,42 v=10,56
+p=74,99 v=91,49
+p=84,6 v=99,94
+p=72,99 v=43,8
+p=4,29 v=76,33
+p=93,97 v=99,-49
+p=25,82 v=-59,65
+p=38,29 v=74,95
+p=45,83 v=74,-80
+p=71,76 v=82,23
+p=83,30 v=86,-24
+p=32,80 v=-77,25
+p=48,50 v=55,-47
+p=95,7 v=21,-73
+p=61,97 v=-6,44
+p=9,16 v=-11,-50
+p=90,97 v=-79,86
+p=58,31 v=-69,35
+p=38,49 v=-72,18
+p=91,5 v=99,85
+p=29,62 v=-31,43
+p=45,66 v=33,-42
+p=67,83 v=73,-57
+p=23,3 v=6,7
+p=57,32 v=-60,-89
+p=83,54 v=-33,-24
+p=28,4 v=57,49
+p=100,97 v=-62,-77
+p=89,71 v=-21,-25
+p=94,39 v=-6,-27
+p=71,41 v=-1,-90
+p=87,39 v=-98,-68
+p=72,43 v=54,98
+p=78,91 v=-22,-83
+p=29,58 v=-64,-26
+p=21,2 v=-3,71
+p=38,6 v=2,-40
+p=75,62 v=96,99
+p=4,22 v=39,53
+p=63,73 v=-60,23
+p=26,38 v=2,-94
+p=94,16 v=-65,-30
+p=11,101 v=89,89
+p=48,38 v=-91,29
+p=64,15 v=-47,-95
+p=79,78 v=91,23
+p=92,72 v=58,-58
+p=2,76 v=99,24
+p=89,6 v=31,33
+p=98,79 v=90,4
+p=78,30 v=-83,-66
+p=77,44 v=27,77
+p=99,0 v=44,73
+p=33,72 v=93,22
+p=9,97 v=-92,-96
+p=84,13 v=35,-87
+p=68,97 v=-19,-95
+p=68,61 v=-72,-30
+p=26,13 v=65,-66
+p=85,94 v=-25,74
+p=42,20 v=74,-8
+p=63,58 v=-10,93
+p=6,83 v=-62,-97
+p=42,54 v=90,-97
+p=10,78 v=-32,-99
+p=43,16 v=-26,6
+p=40,68 v=-36,62
+p=32,42 v=-26,27
+p=69,69 v=73,85
+p=78,78 v=-42,68
+p=51,34 v=-95,57
+p=88,41 v=-75,-44
+p=80,86 v=-65,22
+p=33,95 v=-22,-54
+p=86,56 v=-89,18
+p=93,0 v=90,-55
+p=22,89 v=48,29
+p=6,39 v=-43,-44
+p=70,19 v=51,97
+p=67,31 v=82,14
+p=8,80 v=-30,66
+p=65,7 v=-5,52
+p=17,62 v=7,-84
+p=93,96 v=-25,6
+p=86,3 v=-44,-29
+p=73,18 v=32,33
+p=41,62 v=4,-5
+p=88,72 v=-45,23
+p=79,86 v=77,87
+p=43,95 v=-55,65
+p=61,72 v=22,3
+p=32,74 v=67,27
+p=9,59 v=-11,-63
+p=31,86 v=24,85
+p=34,26 v=-45,80
+p=56,78 v=-55,-70
+p=73,91 v=-47,-77
+p=5,98 v=81,48
+p=63,77 v=13,22
+p=2,70 v=-39,-95
+p=90,46 v=95,14
+p=1,32 v=72,16
+p=1,102 v=-16,71
+p=44,5 v=-96,-75
+p=7,9 v=35,49
+p=23,92 v=84,-94
+p=68,2 v=-52,33
+p=99,85 v=90,-98
+p=30,80 v=-31,67
+p=44,19 v=10,-71
+p=70,80 v=-42,5
+p=82,22 v=48,9
+p=60,9 v=-60,89
+p=4,80 v=94,45
+p=19,66 v=-3,-84
+p=71,23 v=59,33
+p=41,42 v=92,-47

2024/day14/test.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