feat: solve part one

internal/2015/DaySix/code.go

@@ -0,0 +1,75 @@
+package daysix
+
+import (
+	"advent-of-code/internal/registry"
+	"os"
+	"strconv"
+	"strings"
+)
+
+func init() {
+	registry.Register("2015D6", ParseInput, PartOne, PartTwo)
+}
+
+func ParseInput(filepath string) []string {
+	content, _ := os.ReadFile(filepath)
+	return strings.Split(strings.TrimSpace(string(content)), "\n")
+}
+
+func PartOne(data []string) int {
+	grid := make([]bool, 1000*1000)
+
+	for _, line := range data {
+		var op string
+		var x1, y1, x2, y2 int
+
+		switch {
+		case strings.HasPrefix(line, "turn on "):
+			op = "on"
+			line = strings.TrimPrefix(line, "turn on ")
+		case strings.HasPrefix(line, "turn off "):
+			op = "off"
+			line = strings.TrimPrefix(line, "turn off ")
+		case strings.HasPrefix(line, "toggle "):
+			op = "toggle"
+			line = strings.TrimPrefix(line, "toggle ")
+		default:
+			continue
+		}
+
+		parts := strings.Split(line, " through ")
+		firstCoordinates := strings.Split(parts[0], ",")
+		secondCoordinates := strings.Split(parts[1], ",")
+
+		x1, _ = strconv.Atoi(firstCoordinates[0])
+		y1, _ = strconv.Atoi(firstCoordinates[1])
+		x2, _ = strconv.Atoi(secondCoordinates[0])
+		y2, _ = strconv.Atoi(secondCoordinates[1])
+
+		for y := y1; y <= y2; y++ {
+			for x := x1; x <= x2; x++ {
+				idx := y*1000 + x
+				switch op {
+				case "on":
+					grid[idx] = true
+				case "off":
+					grid[idx] = false
+				case "toggle":
+					grid[idx] = !grid[idx]
+				}
+			}
+		}
+	}
+
+	count := 0
+	for _, lit := range grid {
+		if lit {
+			count++
+		}
+	}
+	return count
+}
+
+func PartTwo(data []string) int {
+	return 0
+}

internal/2015/DaySix/code_test.go

@@ -0,0 +1,17 @@
+package daysix
+
+import "testing"
+
+var testInput = []string{
+	"turn on 0,0 through 999,999",
+	"toggle 0,0 through 999,0",
+	"turn off 499,499 through 500,500",
+}
+
+func TestPartOne(t *testing.T) {
+	expected := 998996
+	got := PartOne(testInput)
+	if got != expected {
+		t.Errorf("PartOne() = %d, want %d", got, expected)
+	}
+}