day 22 part 1 is tractable; part 2 is going to need a rethink

22/main.go

@@ -0,0 +1,134 @@
+package main
+
+import (
+	"bufio"
+	"fmt"
+	"os"
+	"strconv"
+	"time"
+)
+
+func mustAtoi(line string) int {
+	i, _ := strconv.Atoi(line)
+	return i
+}
+
+func main() {
+	start := time.Now()
+	partOne()
+	duration := time.Since(start)
+	partTwo()
+	duration2 := time.Since(start)
+	fmt.Printf("p1: %s, p2: %s\n", duration, duration2-duration)
+}
+
+func makeScanner(test bool) *bufio.Scanner {
+	var f *os.File
+	if test {
+		f, _ = os.Open("inputs/testinput")
+	} else {
+		f, _ = os.Open("inputs/input")
+	}
+	reader := bufio.NewReader(f)
+	return bufio.NewScanner(reader)
+}
+
+type step struct {
+	on bool
+	x  []int
+	y  []int
+	z  []int
+}
+
+func ParseInput(line string) step {
+	s := step{}
+	var state byte
+	acc := ""
+	for i := 0; i < len(line); i++ {
+		switch line[i] {
+		case '1', '2', '3', '4', '5', '6', '7', '8', '9', '0', '-':
+			acc += string(line[i])
+		case 'f':
+			s.on = false
+		case 'n':
+			s.on = true
+		case 'x', 'y', 'z':
+			state = line[i]
+		case '.', ',':
+			if line[i] == '.' {
+				i++ // skip second .
+			}
+			switch state {
+			case 'x':
+				s.x = append(s.x, mustAtoi(acc))
+			case 'y':
+				s.y = append(s.y, mustAtoi(acc))
+			case 'z':
+				s.z = append(s.z, mustAtoi(acc))
+			}
+			acc = ""
+		default: // all other characters do nothing
+		}
+	}
+	s.z = append(s.z, mustAtoi(acc)) // catch last number
+	return s
+}
+
+type coord struct {
+	x int
+	y int
+	z int
+}
+
+func GenerateCoords(s step) []coord {
+	c := []coord{}
+	for x := s.x[0]; x <= s.x[1]; x++ {
+		for y := s.y[0]; y <= s.y[1]; y++ {
+			for z := s.z[0]; z <= s.z[1]; z++ {
+				c = append(c, coord{x, y, z})
+			}
+		}
+	}
+	return c
+}
+
+func partOne() {
+	scanner := makeScanner(true)
+
+	grid := map[coord]struct{}{}
+	steps := []step{}
+	for scanner.Scan() {
+		steps = append(steps, ParseInput(scanner.Text()))
+	}
+	for _, step := range steps[0:20] {
+		for _, coord := range GenerateCoords(step) {
+			if step.on {
+				grid[coord] = struct{}{}
+			} else {
+				delete(grid, coord)
+			}
+		}
+	}
+	fmt.Println(len(grid))
+}
+
+func partTwo() {
+	scanner := makeScanner(true)
+
+	grid := map[coord]struct{}{}
+	steps := []step{}
+	for scanner.Scan() {
+		steps = append(steps, ParseInput(scanner.Text()))
+	}
+	// this ain't gonna work
+	for _, step := range steps {
+		for _, coord := range GenerateCoords(step) {
+			if step.on {
+				grid[coord] = struct{}{}
+			} else {
+				delete(grid, coord)
+			}
+		}
+	}
+	fmt.Println(len(grid))
+}