day10, reading & printing

day10/dayTen.go

@@ -0,0 +1,143 @@
+package day10
+
+import (
+	"errors"
+	"fmt"
+	"os"
+	"strings"
+)
+
+func Run() int {
+	fmt.Println("hello day 10")
+	// filename := "day10/example2noisy"
+	filename := "day10/example1"
+	fieldMap := Read(filename)
+	fmt.Println(fieldMap.String())
+
+	return 0
+}
+
+// so do i work with just [][]rune ?
+// func Next(from Coord, through Coord) (Coord, error) ?
+// and here check that 'from' has exit into 'through'
+// and check that 'through' has entrance from 'from'
+
+// so, i guess i could do 'exit direction' and 'entrance direction'
+// then compare 'exit direction' with what's available on 'from'
+//
+// or i can just have function 'canExit(from, to Coord)' and canEnter(from, to Coord)
+
+// i suppose it would be nice to just create Cell(Coord, Type) and
+// cell would map 'from' to 'to'
+
+type Cell struct {
+	Coord Coord
+	Tile  rune
+}
+func (c *Cell)String() string {
+	switch c.Tile {
+    case '7': return "⌝"
+    case 'J': return "⌟"
+    case 'F': return "⌜"
+    case 'L': return "⌞"
+    case '.': return " "
+    default: return string(c.Tile)
+	}
+}
+type Coord struct {
+	X, Y int
+}
+
+type Map struct {
+	Cells         map[Coord]Cell
+	Height, Width int
+	BeastCoord    Coord
+}
+func (m *Map)String() string {
+	result := ""
+	for y := 0; y < m.Height; y++ {
+		for x := 0; x < m.Width; x++ {
+			cell := m.Cells[Coord{x, y}]
+			result += cell.String()
+		}
+		result += "\n"
+	}
+	return result
+}
+
+func Read(filename string) Map {
+	result := Map{}
+	bytes, err := os.ReadFile(filename)
+	if err != nil {
+		panic(fmt.Sprint("cannot read file ", filename))
+	}
+	lines := strings.Split(string(bytes), "\n")
+	result.Height = len(lines)
+	result.Width = len(lines[0])
+	result.Cells = map[Coord]Cell{}
+
+	for y, line := range lines {
+		for x, symb := range line {
+			coord := Coord{X: x, Y: y}
+			if symb == 'S' {
+				result.BeastCoord = coord
+			}
+			result.Cells[coord] = Cell{
+				Coord: coord,
+				Tile:  symb,
+			}
+		}
+	}
+
+	return result
+}
+
+// doesn't check whether 'from' has exit into c
+// only whether c can accept conntion from that direction
+func (c *Cell) Next(from Coord) (to Coord, err error) {
+	nextCoord, found := c.Directions()[from]
+	if !found {
+		return Coord{}, errors.New(fmt.Sprintf("no direction from %+v to %+v through %+v\n", from, to, c))
+	}
+
+	return nextCoord, nil
+}
+
+// x from left to right; y from top to bottom
+func (c *Cell) Directions() map[Coord]Coord {
+	x, y := c.Coord.X, c.Coord.Y
+	switch c.Tile {
+	case '|':
+		return map[Coord]Coord{
+			{x, y + 1}: {x, y - 1},
+			{x, y - 1}: {x, y + 1},
+		}
+	case '-':
+		return map[Coord]Coord{
+			{x - 1, y}: {x + 1, y},
+			{x + 1, y}: {x - 1, y},
+		}
+	case 'L':
+		return map[Coord]Coord{
+			{x, y + 1}: {x + 1, y},
+			{x + 1, y}: {x, y + 1},
+		}
+	case 'J':
+		return map[Coord]Coord{
+			{x, y + 1}: {x - 1, y},
+			{x - 1, y}: {x, y + 1},
+		}
+	case 'F':
+		return map[Coord]Coord{
+			{x + 1, y}: {x, y + 1},
+			{x, y + 1}: {x + 1, y},
+		}
+	case '7':
+		return map[Coord]Coord{
+			{x - 1, y}: {x, y + 1},
+			{x, y + 1}: {x - 1, y},
+		}
+	default:
+		return map[Coord]Coord{}
+	}
+}

day10/example1

@@ -0,0 +1,5 @@
+.....
+.S-7.
+.|.|.
+.L-J.
+.....

day10/example2noisy

@@ -0,0 +1,5 @@
+-L|F7
+7S-7|
+L|7||
+-L-J|
+L|-JF

day10/example3

@@ -0,0 +1,5 @@
+..F7.
+.FJ|.
+SJ.L7
+|F--J
+LJ...

day10/example4noisy

@@ -0,0 +1,5 @@
+7-F7-
+.FJ|7
+SJLL7
+|F--J
+LJ.LJ

main.go

@@ -3,12 +3,12 @@ package main
 import (
 	"log"
 
-	"sunshine.industries/aoc2023/day9"
+	"sunshine.industries/aoc2023/day10"
 )
 
 func main() {
 	log.Print("> starting run:")
 
-	result := day9.Run2()
-	log.Printf("day9 result: %d\n****\n", result)
+	result := day10.Run()
+	log.Printf("day10 result: %d\n****\n", result)
 }