86 lines
1.8 KiB
Go
86 lines
1.8 KiB
Go
package main
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import (
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"container/list"
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"fmt"
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"image"
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"os"
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"strings"
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)
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func main() {
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data, _ := os.ReadFile("input")
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answer := solution(data, 64)
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fmt.Println("# Part 1")
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fmt.Println(answer[0])
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fmt.Println("# Part 2")
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fmt.Println(answer[1])
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}
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func solution(data []byte, total_steps int) []int {
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lines := strings.Split(strings.TrimSpace(string(data)), "\n")
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q := list.New()
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symbols := map[image.Point]string{}
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for y, line := range lines {
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l := strings.TrimSpace(line)
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//fmt.Println(len(s))
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for x, r := range l {
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symbols[image.Point{x, y}] = string(r)
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if r == 'S' {
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q.PushBack(image.Point{x, y})
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}
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}
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}
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steps := 0
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total := 26501365
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part_1 := 0
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part_2 := 0
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directions := []image.Point{
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{-1, 0}, {0, -1}, {0, 1}, {1, 0},
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}
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polynomial := make([]int, 0)
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for steps < total {
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new_Q := list.New()
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visited := make(map[image.Point]bool)
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for q.Len() > 0 {
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element := q.Front()
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val := element.Value.(image.Point)
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q.Remove(element)
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x, y := val.X, val.Y
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for _, d := range directions {
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newPos := image.Point{x + d.X, y + d.Y}
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ref := image.Point{((newPos.Y % len(lines)) + len(lines)) % len(lines), ((newPos.X % len(lines)) + len(lines)) % len(lines)}
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if symbols[ref] != "#" {
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if _, ok := visited[newPos]; !ok {
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visited[newPos] = true
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new_Q.PushBack(newPos)
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}
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}
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}
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}
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steps += 1
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q = new_Q //update queue
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if steps%(len(lines)) == total%len(lines) {
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polynomial = append(polynomial, len(visited))
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if len(polynomial) == 3 {
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p0 := polynomial[0]
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p1 := polynomial[1] - polynomial[0]
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p2 := polynomial[2] - polynomial[1]
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part_2 = p0 + (p1 * (total / len(lines))) + ((total/len(lines))*((total/len(lines))-1)/2)*(p2-p1)
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break
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}
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}
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if steps == total_steps {
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part_1 = len(visited)
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}
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}
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return []int{part_1, part_2}
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}
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