day 3 part 2

day03p2/solution.go

@@ -0,0 +1,46 @@
+package day03p2
+
+import (
+	"io"
+	"regexp"
+	"strconv"
+
+	"aoc/utils"
+)
+
+func Solve(r io.Reader) any {
+	lines := utils.ReadLines(r)
+	sum := 0
+
+	cumulStr := ""
+	for _, line := range lines {
+		cumulStr += line
+	}
+
+	instructionRegex, _ := regexp.Compile(`(mul\((\d+),(\d+)\)|do\(\)|don't\(\))`)
+	matches := instructionRegex.FindAllStringSubmatch(cumulStr, -1)
+
+	mulEnabled := true
+
+	for _, match := range matches {
+		instruction := match[1]
+
+		if instruction == "do()" {
+			mulEnabled = true
+		} else if instruction == "don't()" {
+			mulEnabled = false
+		} else if match[2] != "" && match[3] != "" {
+			if mulEnabled {
+				x, _ := strconv.Atoi(match[2])
+				y, _ := strconv.Atoi(match[3])
+				sum += x * y
+			}
+		}
+	}
+
+	return sum
+}
+
+func ArrayIsEmpty(a []int) bool {
+	return len(a) == 0
+}

day03p2/solution_test.go

@@ -0,0 +1,33 @@
+package day03p2
+
+import (
+	"strings"
+	"testing"
+
+	"aoc/utils"
+)
+
+var testInput = `xmul(2,4)&mul[3,7]!^don't()_mul(5,5)+mul(32,64](mul(11,8)undo()?mul(8,5))`
+
+func TestSolve(t *testing.T) {
+	tests := []struct {
+		input  string
+		answer int
+	}{
+		{testInput, 48},
+	}
+
+	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)
+		}
+	}
+}