updates

2024/go/day13/day13.go

@@ -0,0 +1,58 @@
+package day13
+
+import (
+	"adventofcode2024/utils"
+	_ "adventofcode2024/utils/grid2d"
+	_ "adventofcode2024/utils/inputs"
+	"regexp"
+	_ "fmt"
+	"strings"
+)
+
+func Part1(input string) int {
+	val := 0
+	machines := strings.Split(input, "\n\n")
+	pattern := `Button A: X\+(\d+), Y\+(\d+)\sButton B: X\+(\d+), Y\+(\d+)\sPrize: X=(\d+), Y=(\d+)`
+	re := regexp.MustCompile(pattern)
+	for _, machine := range machines {
+		matches := re.FindStringSubmatch(machine)
+		a := utils.MustAtoi(matches[1])
+		b := utils.MustAtoi(matches[2])
+		c := utils.MustAtoi(matches[3])
+		d := utils.MustAtoi(matches[4])
+		X := utils.MustAtoi(matches[5])
+		Y := utils.MustAtoi(matches[6])
+//		fmt.Println(matches)
+		B := (Y*a - X*b)/(a*d - c*b)
+		A := (X - c*B)/a
+//		fmt.Printf("A: %d B: %d\n", A, B)
+		if (A*a + B*c == X && A*b + B*d == Y) {
+			val += A*3 + B
+		}
+	}
+	return val
+}
+
+func Part2(input string) int {
+	val := 0
+	machines := strings.Split(input, "\n\n")
+	pattern := `Button A: X\+(\d+), Y\+(\d+)\sButton B: X\+(\d+), Y\+(\d+)\sPrize: X=(\d+), Y=(\d+)`
+	re := regexp.MustCompile(pattern)
+	for _, machine := range machines {
+		matches := re.FindStringSubmatch(machine)
+		a := utils.MustAtoi(matches[1])
+		b := utils.MustAtoi(matches[2])
+		c := utils.MustAtoi(matches[3])
+		d := utils.MustAtoi(matches[4])
+		X := utils.MustAtoi(matches[5]) + 10000000000000
+		Y := utils.MustAtoi(matches[6]) + 10000000000000
+//		fmt.Println(matches)
+		B := (Y*a - X*b)/(a*d - c*b)
+		A := (X - c*B)/a
+//		fmt.Printf("A: %d B: %d\n", A, B)
+		if (A*a + B*c == X && A*b + B*d == Y) {
+			val += A*3 + B
+		}
+	}
+	return val
+}

2024/go/day13/day13_test.go

@@ -0,0 +1,45 @@
+package day13
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestPart1(t *testing.T) {
+	r := Part1(`Button A: X+94, Y+34
+Button B: X+22, Y+67
+Prize: X=8400, Y=5400
+
+Button A: X+26, Y+66
+Button B: X+67, Y+21
+Prize: X=12748, Y=12176
+
+Button A: X+17, Y+86
+Button B: X+84, Y+37
+Prize: X=7870, Y=6450
+
+Button A: X+69, Y+23
+Button B: X+27, Y+71
+Prize: X=18641, Y=10279`)
+	require.Equal(t, 480, r)
+}
+
+func TestPart2(t *testing.T) {
+	r := Part2(`Button A: X+94, Y+34
+Button B: X+22, Y+67
+Prize: X=8400, Y=5400
+
+Button A: X+26, Y+66
+Button B: X+67, Y+21
+Prize: X=12748, Y=12176
+
+Button A: X+17, Y+86
+Button B: X+84, Y+37
+Prize: X=7870, Y=6450
+
+Button A: X+69, Y+23
+Button B: X+27, Y+71
+Prize: X=18641, Y=10279`)
+	require.Equal(t, 480, r)
+}