130 lines
1.9 KiB
Go
130 lines
1.9 KiB
Go
package main
|
|
|
|
import (
|
|
"bufio"
|
|
"fmt"
|
|
"io"
|
|
"os"
|
|
"strings"
|
|
)
|
|
|
|
type Position struct {
|
|
X, Y int
|
|
}
|
|
|
|
type Spot bool
|
|
|
|
const (
|
|
Tree Spot = true
|
|
Open = false
|
|
)
|
|
|
|
type Map [][]Spot
|
|
|
|
func ReadMapFromFile(file string) *Game {
|
|
f, err := os.Open(file)
|
|
if err != nil {
|
|
panic(err)
|
|
}
|
|
defer f.Close()
|
|
r := bufio.NewReader(f)
|
|
m := Map{}
|
|
for {
|
|
line, err := r.ReadString('\n')
|
|
if err == io.EOF {
|
|
break
|
|
}
|
|
if err != nil {
|
|
panic(err)
|
|
}
|
|
line = strings.TrimSpace(line)
|
|
row := []Spot{}
|
|
for _, c := range line {
|
|
switch c {
|
|
case '.':
|
|
row = append(row, Open)
|
|
case '#':
|
|
row = append(row, Tree)
|
|
default:
|
|
panic("wrong character")
|
|
}
|
|
}
|
|
m = append(m, row)
|
|
}
|
|
return &Game{Map: m}
|
|
}
|
|
|
|
func (m Map) DY() int {
|
|
return len(m)
|
|
}
|
|
|
|
func (m Map) DX() int {
|
|
maxX := 0
|
|
for i := 0; i < len(m); i++ {
|
|
if len(m[i]) > maxX {
|
|
maxX = len(m[i])
|
|
}
|
|
}
|
|
return maxX
|
|
}
|
|
|
|
type Game struct {
|
|
Map Map
|
|
Position Position
|
|
}
|
|
|
|
func (g *Game) GetCurrentSpot() Spot {
|
|
return g.Map[g.Position.Y%g.Map.DY()][g.Position.X%g.Map.DX()]
|
|
}
|
|
|
|
func (g *Game) MoveRight(d int) {
|
|
g.Position.X += d
|
|
}
|
|
|
|
func (g *Game) MoveDown(d int) {
|
|
g.Position.Y += d
|
|
}
|
|
|
|
func main() {
|
|
game := ReadMapFromFile("input")
|
|
|
|
moveRuleSet := [][]int{
|
|
{1, 1},
|
|
{3, 1},
|
|
{5, 1},
|
|
{7, 1},
|
|
{1, 2},
|
|
}
|
|
|
|
results := []int{}
|
|
|
|
for _, ruleSet := range moveRuleSet {
|
|
treesEncountered := 0
|
|
|
|
dx := ruleSet[0]
|
|
dy := ruleSet[1]
|
|
|
|
game.Position.X = 0
|
|
game.Position.Y = 0
|
|
|
|
for game.Position.Y < game.Map.DY() {
|
|
if game.GetCurrentSpot() == Tree {
|
|
treesEncountered++
|
|
}
|
|
game.MoveRight(dx)
|
|
game.MoveDown(dy)
|
|
}
|
|
|
|
results = append(results, treesEncountered)
|
|
fmt.Printf("%d trees encountered\n", treesEncountered)
|
|
}
|
|
|
|
product := results[0]
|
|
fmt.Printf("%d\n", product)
|
|
for i := 1; i < len(results); i++ {
|
|
product *= results[i]
|
|
fmt.Printf(" * %d = %d\n", results[i], product)
|
|
}
|
|
fmt.Printf(" = %d\n", product)
|
|
}
|