2021 day 13,15,16. need to clean up this code quite a bit

2021/day13/main.go

@@ -0,0 +1,149 @@
+package main
+
+import (
+	_ "embed"
+	"flag"
+	"fmt"
+	"regexp"
+	"strings"
+
+	"github.com/alexchao26/advent-of-code-go/cast"
+	"github.com/alexchao26/advent-of-code-go/util"
+)
+
+//go:embed input.txt
+var input string
+
+func init() {
+	// do this in init (not main) so test file has same input
+	input = strings.TrimRight(input, "\n")
+	if len(input) == 0 {
+		panic("empty input.txt file")
+	}
+}
+
+func main() {
+	var part int
+	flag.IntVar(&part, "part", 1, "part 1 or 2")
+	flag.Parse()
+	fmt.Println("Running part", part)
+
+	if part == 1 {
+		ans := part1(input)
+		util.CopyToClipboard(fmt.Sprintf("%v", ans))
+		fmt.Println("Output:", ans)
+	} else {
+		ans := part2(input)
+		util.CopyToClipboard(fmt.Sprintf("%v", ans))
+		fmt.Println("Output:", ans)
+	}
+}
+
+func part1(input string) int {
+	parts := strings.Split(input, "\n\n")
+
+	coords := map[[2]int]bool{}
+	// parse coords
+	for _, line := range strings.Split(parts[0], "\n") {
+		sp := strings.Split(line, ",")
+		coords[[2]int{cast.ToInt(sp[0]), cast.ToInt(sp[1])}] = true
+	}
+	fmt.Println(len(coords))
+
+	// // printing is a pita
+	// grid := make([][]int, 15)
+	// for i := range grid {
+	// 	grid[i] = make([]int, 15)
+	// }
+	// for c := range coords {
+	// 	grid[c[1]][c[0]] = 1
+	// }
+	// for _, row := range grid {
+	// 	fmt.Println(row)
+	// }
+
+	for _, fold := range strings.Split(parts[1], "\n") {
+		cap := regexp.MustCompile(`fold along (x|y)=(\d+)`).FindStringSubmatch(fold)
+		// remove full match
+		cap = cap[1:]
+
+		dir := cap[0]
+		foldCoord := cast.ToInt(cap[1])
+
+		fmt.Println("folding on", dir, foldCoord)
+
+		// fmt.Println(fold, dir, line)
+		// dots will never appear exactly on a fold line
+		isFoldOnX := dir == "x"
+		nextMap := map[[2]int]bool{}
+		if isFoldOnX {
+			for c := range coords {
+				if c[0] > foldCoord {
+					folded := [2]int{
+						foldCoord - (c[0] - foldCoord),
+						c[1],
+					}
+					fmt.Println(c, "to", folded)
+					nextMap[folded] = true
+				} else {
+					nextMap[c] = true
+				}
+			}
+		} else {
+			// fold on y
+			for c := range coords {
+				if c[1] > foldCoord {
+					folded := [2]int{
+						c[0],
+						foldCoord - (c[1] - foldCoord),
+					}
+					fmt.Println(c, "to", folded)
+					nextMap[folded] = true
+				} else {
+					nextMap[c] = true
+				}
+			}
+		}
+
+		coords = nextMap
+
+		// TODO just break for part 1
+		// break
+	}
+
+	// printing is a pita
+	max := 0
+	for c := range coords {
+		if c[0] > max {
+			max = c[0]
+		}
+		if c[1] > max {
+			max = c[1]
+		}
+	}
+
+	grid := make([][]int, max+1)
+	for i := range grid {
+		grid[i] = make([]int, max+1)
+	}
+	for c := range coords {
+		grid[c[1]][c[0]] = 1
+	}
+	for _, row := range grid {
+		str := ""
+		for _, val := range row {
+			if val == 1 {
+				str += "#"
+			} else {
+				str += "."
+			}
+		}
+		fmt.Println(str)
+	}
+
+	return len(coords)
+}
+
+func part2(input string) int {
+	return 0
+}