day 14p1

day14p1/solution.go

@@ -0,0 +1,66 @@
+package day14p1
+
+import (
+	"io"
+
+	"aoc/utils"
+)
+
+func Solve(r io.Reader) any {
+	lines := utils.ReadLines(r)
+	isTest := len(lines) == 12
+	boardWidth := 11
+	if !isTest {
+		boardWidth = 101
+	}
+	boardHeight := 7
+	if !isTest {
+		boardHeight = 103
+	}
+
+	endPoints := make(map[utils.Point]int)
+
+	for _, line := range lines {
+		ints := utils.GetInts(line)
+		px, py, vx, vy := ints[0], ints[1], ints[2], ints[3]
+		for range 100 {
+			px += vx
+			py += vy
+			if px < 0 {
+				px += boardWidth
+			} else if px >= boardWidth {
+				px -= boardWidth
+			}
+			if py < 0 {
+				py += boardHeight
+			} else if py >= boardHeight {
+				py -= boardHeight
+			}
+		}
+		endPoints[utils.Point{X: px, Y: py}]++
+	}
+
+	bots := make([]int, 4)
+
+	for point, count := range endPoints {
+		if point.X < boardWidth/2 && point.Y < boardHeight/2 {
+			bots[0] += count
+		} else if point.X > boardWidth/2 && point.Y < boardHeight/2 {
+			bots[1] += count
+		} else if point.X < boardWidth/2 && point.Y > boardHeight/2 {
+			bots[2] += count
+		} else if point.X > boardWidth/2 && point.Y > boardHeight/2 {
+			bots[3] += count
+		}
+	}
+
+	return multAll(bots)
+}
+
+func multAll(arr []int) int {
+	result := 1
+	for _, n := range arr {
+		result *= n
+	}
+	return result
+}

day14p1/solution_test.go

@@ -0,0 +1,44 @@
+package day14p1
+
+import (
+	"strings"
+	"testing"
+
+	"aoc/utils"
+)
+
+var testInput = `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`
+
+func TestSolve(t *testing.T) {
+	tests := []struct {
+		input  string
+		answer int
+	}{
+		{testInput, 12},
+	}
+
+	if testing.Verbose() {
+		utils.Verbose = true
+	}
+
+	for _, test := range tests {
+		r := strings.NewReader(test.input)
+
+		result := Solve(r).(int)
+
+		if result != test.answer {
+			t.Errorf("Expected %d, got %d", test.answer, result)
+		}
+	}
+}

utils/functions.go

@@ -6,8 +6,13 @@ import (
 	"bufio"
 	"fmt"
 	"io"
+	"regexp"
+	"strconv"
 )
 
+// regex for integers
+var intRegex = regexp.MustCompile(`-?\d+`)
+
 // Greatest Common Denominator
 func Gcd(a, b int64) int64 {
 	for b != 0 {
@@ -55,3 +60,20 @@ func ReadLines(r io.Reader) []string {
 
 	return result
 }
+
+func GetInts(s string) []int {
+	matches := intRegex.FindAllString(s, -1)
+	result := make([]int, len(matches))
+	for i, match := range matches {
+		result[i] = Atoi(match)
+	}
+
+	return result
+}
+
+func Atoi(s string) int {
+	result, err := strconv.Atoi(s)
+	Check(err, "error converting %s to int", s)
+
+	return result
+}