113 lines
2.0 KiB
Go
113 lines
2.0 KiB
Go
package main
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import (
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"bufio"
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"fmt"
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"os"
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"time"
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)
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func main() {
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start := time.Now()
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partOne()
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duration := time.Since(start)
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fmt.Printf("p1: %s\n", duration)
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}
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func makeScanner(test bool) *bufio.Scanner {
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var f *os.File
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if test {
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f, _ = os.Open("inputs/testinput")
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} else {
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f, _ = os.Open("inputs/input")
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}
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reader := bufio.NewReader(f)
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return bufio.NewScanner(reader)
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}
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type coord struct {
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x int
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y int
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}
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type floor struct {
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steps int
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width int
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height int
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m map[coord]rune
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}
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func (f *floor) Print() {
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for y := 0; y < f.height; y++ {
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for x := 0; x < f.width; x++ {
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fmt.Printf("%s", string(f.m[coord{x: x, y: y}]))
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}
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fmt.Printf("\n")
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}
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fmt.Printf("\n")
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}
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func (f *floor) Step() bool {
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f.steps++
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movedThisStep := map[coord]struct{}{}
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toMove := map[coord]coord{}
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for y := 0; y < f.height; y++ {
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for x := 0; x < f.width; x++ {
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current := coord{x: x, y: y}
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x += 1
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if x >= f.width {
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x = 0
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}
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next := coord{x: x, y: y}
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if _, ok := movedThisStep[current]; !ok && f.m[current] == '>' && f.m[next] == '.' {
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toMove[current] = next
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}
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}
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}
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for current, next := range toMove {
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f.m[next] = f.m[current]
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f.m[current] = '.'
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movedThisStep[next] = struct{}{}
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}
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toMove = map[coord]coord{}
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for y := 0; y < f.height; y++ {
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for x := 0; x < f.width; x++ {
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current := coord{x: x, y: y}
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y += 1
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if y >= f.height {
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y = 0
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}
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next := coord{x: x, y: y}
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if _, ok := movedThisStep[current]; !ok && f.m[current] == 'v' && f.m[next] == '.' {
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toMove[current] = next
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}
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}
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}
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for current, next := range toMove {
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f.m[next] = f.m[current]
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f.m[current] = '.'
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movedThisStep[next] = struct{}{}
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}
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return len(movedThisStep) > 0
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}
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func partOne() {
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scanner := makeScanner(false)
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f := &floor{
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m: make(map[coord]rune),
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}
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y := 0
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for scanner.Scan() {
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line := scanner.Text()
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f.width = len(line)
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for x, v := range line {
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f.m[coord{x: x, y: y}] = v
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}
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y++
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}
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f.height = y
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for f.Step() {
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}
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fmt.Println(f.steps)
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}
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