Day 17 solution
My initial idea for a solution ended up working out great, but I had a hard time getting it all down on "paper," so to speak, so this is probably 200 lines of code too many, but it definitely does exactly what I envisioned (and quickly) even if it's not the most succinct.
This commit is contained in:
422
days/17.go
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422
days/17.go
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package days
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import (
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"fmt"
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"strings"
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u "parnic.com/aoc2019/utilities"
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)
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type camViewCellType int
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type botFacing int
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type day17Grid [][]camViewCellType
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const (
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cellTypeScaffold camViewCellType = iota
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cellTypeOpen
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cellTypeInvalid
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)
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const (
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botFacingUp botFacing = iota
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botFacingLeft
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botFacingDown
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botFacingRight
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botFacingFirst = botFacingUp
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botFacingLast = botFacingRight
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)
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const (
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dirLeft = 1
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dirRight = -1
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maxInstructionSetLength = 20
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)
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var (
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day17AdjacentOffsets = []u.Vec2i{
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{X: -1, Y: 0},
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{X: 1, Y: 0},
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{X: 0, Y: -1},
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{X: 0, Y: 1},
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}
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)
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type Day17 struct {
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program u.IntcodeProgram
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}
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func (d *Day17) Parse() {
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d.program = u.LoadIntcodeProgram("17p")
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}
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func (d Day17) Num() int {
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return 17
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}
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func (currentDir botFacing) getNewFacingDir(turnDir int) botFacing {
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currentDir += botFacing(turnDir)
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if currentDir < botFacingFirst {
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currentDir = botFacingLast
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} else if currentDir > botFacingLast {
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currentDir = botFacingFirst
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}
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return currentDir
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}
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func (grid day17Grid) Draw(botLocation u.Vec2i, botFacingDir botFacing, endLocation u.Vec2i) {
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for y := range grid {
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for x := range grid[y] {
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switch grid[y][x] {
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case cellTypeOpen:
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fmt.Print(" ")
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case cellTypeScaffold:
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char := "█"
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color := u.ColorBlack
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if botLocation.X == x && botLocation.Y == y {
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switch botFacingDir {
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case botFacingUp:
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char = "^"
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case botFacingLeft:
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char = "<"
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case botFacingDown:
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char = "v"
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case botFacingRight:
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char = ">"
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}
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} else if endLocation.X == x && endLocation.Y == y {
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char = "@"
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} else {
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color = u.ColorWhite
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}
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fmt.Printf("%s%s%s%s", u.BackgroundWhite, color, char, u.TextReset)
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}
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}
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fmt.Println()
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}
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}
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func (grid day17Grid) getAdjacentScaffolds(y, x int) []u.Vec2i {
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retval := make([]u.Vec2i, 0)
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for _, offset := range day17AdjacentOffsets {
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offY := y + offset.Y
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offX := x + offset.X
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if offY < 0 || offY >= len(grid) ||
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offX < 0 || offX >= len(grid[0]) {
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continue
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}
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if grid[offY][offX] == cellTypeScaffold {
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retval = append(retval, u.Vec2i{X: offX, Y: offY})
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}
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}
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return retval
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}
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func (grid day17Grid) forEachCellOfType(t camViewCellType, f func(y, x int)) {
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for y := range grid {
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for x := range grid[y] {
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if grid[y][x] == t {
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f(y, x)
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}
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}
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}
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}
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func (grid *day17Grid) processGridUpdate(y int, rVal rune, currBotLocation u.Vec2i, currBotFacing botFacing) (int, u.Vec2i, botFacing) {
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grid.appendValue(rVal, y)
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switch rVal {
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case '\n':
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y++
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case '^', '<', 'v', '>':
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currBotLocation = u.Vec2i{X: len((*grid)[y]) - 1, Y: y}
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switch rVal {
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case '^':
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currBotFacing = botFacingUp
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case '<':
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currBotFacing = botFacingLeft
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case 'v':
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currBotFacing = botFacingDown
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case '>':
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currBotFacing = botFacingRight
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}
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}
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return y, currBotLocation, currBotFacing
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}
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func (grid day17Grid) getCellTypeInDirection(y, x int, facingDir botFacing) (camViewCellType, int, int) {
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newX := x
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newY := y
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switch facingDir {
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case botFacingUp:
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newY--
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case botFacingLeft:
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newX--
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case botFacingDown:
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newY++
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case botFacingRight:
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newX++
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}
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if newY < 0 || newY >= len(grid) || newX < 0 || newX >= len(grid[0]) {
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return cellTypeInvalid, newY, newX
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}
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return grid[newY][newX], newY, newX
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}
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func (grid *day17Grid) appendValue(rVal rune, row int) {
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ensureCapacity := func(y int) {
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for len(*grid) <= y {
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*grid = append(*grid, make([]camViewCellType, 0))
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}
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}
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switch rVal {
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case '#':
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ensureCapacity(row)
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(*grid)[row] = append((*grid)[row], cellTypeScaffold)
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case '.':
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ensureCapacity(row)
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(*grid)[row] = append((*grid)[row], cellTypeOpen)
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case '^', '<', 'v', '>':
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ensureCapacity(row)
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(*grid)[row] = append((*grid)[row], cellTypeScaffold)
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}
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}
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func (grid day17Grid) findEndLocation(botLocation u.Vec2i) u.Vec2i {
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var endLocation u.Vec2i
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grid.forEachCellOfType(cellTypeScaffold, func(y, x int) {
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if numSurrounding := len(grid.getAdjacentScaffolds(y, x)); numSurrounding == 1 {
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if botLocation.X != x || botLocation.Y != y {
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endLocation = u.Vec2i{X: x, Y: y}
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}
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}
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})
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return endLocation
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}
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func (grid day17Grid) getTurnDirectionFromCorner(pos u.Vec2i, botFacingDir botFacing) (int, string) {
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adj := grid.getAdjacentScaffolds(pos.Y, pos.X)
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turnDirection := 0
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// this is so awful. i'm sure there's a better way, but i'm tired.
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if botFacingDir == botFacingUp || botFacingDir == botFacingDown {
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if u.ArrayContains(adj, u.Vec2i{X: pos.X - 1, Y: pos.Y}) {
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if botFacingDir == botFacingUp {
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turnDirection = dirLeft
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} else if botFacingDir == botFacingDown {
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turnDirection = dirRight
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}
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} else if u.ArrayContains(adj, u.Vec2i{X: pos.X + 1, Y: pos.Y}) {
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if botFacingDir == botFacingUp {
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turnDirection = dirRight
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} else if botFacingDir == botFacingDown {
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turnDirection = dirLeft
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}
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}
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} else {
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if u.ArrayContains(adj, u.Vec2i{X: pos.X, Y: pos.Y - 1}) {
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if botFacingDir == botFacingLeft {
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turnDirection = dirRight
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} else if botFacingDir == botFacingRight {
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turnDirection = dirLeft
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}
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} else if u.ArrayContains(adj, u.Vec2i{X: pos.X, Y: pos.Y + 1}) {
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if botFacingDir == botFacingLeft {
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turnDirection = dirLeft
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} else if botFacingDir == botFacingRight {
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turnDirection = dirRight
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}
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}
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}
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dirAscii := "L"
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if turnDirection == dirRight {
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dirAscii = "R"
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}
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return turnDirection, dirAscii
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}
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func buildInstructionString(instructions []string) string {
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workingInstructions := make([]string, len(instructions))
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copy(workingInstructions, instructions)
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minimumRecurrence := 3
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initialInstructionSubsetLen := 4
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instructionStr := strings.Join(workingInstructions, ",")
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progs := make([][]string, 3)
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for i := range progs {
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numFound := minimumRecurrence
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subLen := initialInstructionSubsetLen
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for numFound >= minimumRecurrence {
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numFound = 1
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instructionSubset := strings.Join(workingInstructions[0:subLen], ",")
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if len(instructionSubset) > maxInstructionSetLength {
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break
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}
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for x := len(instructionSubset); x <= len(instructionStr)-len(instructionSubset); x++ {
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if instructionStr[x:x+len(instructionSubset)] == instructionSubset {
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numFound++
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x += len(instructionSubset)
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}
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}
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if numFound >= minimumRecurrence {
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subLen += 2
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}
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}
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if numFound < minimumRecurrence {
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subLen -= 2
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}
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progs[i] = make([]string, subLen)
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copy(progs[i], workingInstructions[0:subLen])
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instructionStr = strings.ReplaceAll(instructionStr, strings.Join(progs[i], ","), "")
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instructionStr = strings.TrimPrefix(strings.ReplaceAll(instructionStr, ",,", ","), ",")
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if len(instructionStr) == 0 {
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workingInstructions = nil
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} else {
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workingInstructions = strings.Split(instructionStr, ",")
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}
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}
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if workingInstructions != nil {
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panic("failed to use up all instructions")
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}
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programStr := strings.Join(instructions, ",")
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for i := range progs {
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programStr = strings.ReplaceAll(programStr, strings.Join(progs[i], ","), fmt.Sprintf("%c", 'A'+i))
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}
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sb := strings.Builder{}
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sb.WriteString(programStr)
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sb.WriteRune('\n')
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for i := range progs {
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sb.WriteString(strings.Join(progs[i], ","))
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sb.WriteRune('\n')
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}
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runDebug := 'n'
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sb.WriteRune(runDebug)
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sb.WriteRune('\n')
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return sb.String()
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}
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func (grid day17Grid) solvePath(botLocation u.Vec2i, botFacingDir botFacing) string {
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instructions := make([]string, 0)
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pos := botLocation
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endLocation := grid.findEndLocation(botLocation)
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for {
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if pos == endLocation {
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break
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}
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turnDirection, dirAscii := grid.getTurnDirectionFromCorner(pos, botFacingDir)
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if turnDirection == 0 {
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panic("at an invalid location somehow")
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}
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instructions = append(instructions, dirAscii)
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botFacingDir = botFacingDir.getNewFacingDir(turnDirection)
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numMoved := 0
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for {
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cell, newY, newX := grid.getCellTypeInDirection(pos.Y, pos.X, botFacingDir)
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if cell != cellTypeScaffold {
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break
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}
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pos.X = newX
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pos.Y = newY
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numMoved++
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}
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instructions = append(instructions, fmt.Sprintf("%d", numMoved))
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}
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return buildInstructionString(instructions)
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}
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func (d *Day17) Part1() string {
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grid := day17Grid{}
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y := 0
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var botLocation u.Vec2i
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var botFacingDir botFacing
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d.program.RunIn(func(inputStep int) int64 {
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return 0
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}, func(val int64, state u.IntcodeProgramState) {
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rVal := rune(val)
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y, botLocation, botFacingDir = grid.processGridUpdate(y, rVal, botLocation, botFacingDir)
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})
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alignmentParameterTotal := 0
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grid.forEachCellOfType(cellTypeScaffold, func(y, x int) {
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if numSurrounding := len(grid.getAdjacentScaffolds(y, x)); numSurrounding == 4 {
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alignmentParameterTotal += y * x
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}
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})
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// endLocation := grid.findEndLocation(botLocation)
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// grid.Draw(botLocation, botFacingDir, endLocation)
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return fmt.Sprintf("Alignment parameter sum: %s%d%s", u.TextBold, alignmentParameterTotal, u.TextReset)
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}
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func (d *Day17) Part2() string {
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beforeGrid := day17Grid{}
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var beforeBotLocation u.Vec2i
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var beforeBotFacing botFacing
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afterGrid := day17Grid{}
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var afterBotLocation u.Vec2i
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var afterBotFacing botFacing
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d.program.Reset()
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d.program.SetMemory(0, 2)
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row := 0
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var outputState int
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var lastOutput int64
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var instructionStr string
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d.program.RunIn(func(inputStep int) int64 {
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return int64(instructionStr[inputStep-1])
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}, func(val int64, state u.IntcodeProgramState) {
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rVal := rune(val)
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if outputState == 0 {
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row, beforeBotLocation, beforeBotFacing = beforeGrid.processGridUpdate(row, rVal, beforeBotLocation, beforeBotFacing)
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} else if outputState == 2 {
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row, afterBotLocation, afterBotFacing = afterGrid.processGridUpdate(row, rVal, afterBotLocation, afterBotFacing)
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}
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if rVal == '\n' && lastOutput == '\n' {
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if outputState == 0 {
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instructionStr = beforeGrid.solvePath(beforeBotLocation, beforeBotFacing)
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}
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outputState++
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row = 0
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}
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lastOutput = val
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})
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// fmt.Println("initial grid:")
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// beforeEndLocation := beforeGrid.findEndLocation(beforeBotLocation)
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// beforeGrid.Draw(beforeBotLocation, beforeBotFacing, beforeEndLocation)
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// fmt.Println("completed grid:")
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// afterEndLocation := afterGrid.findEndLocation(afterBotLocation)
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// afterGrid.Draw(afterBotLocation, afterBotFacing, afterEndLocation)
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return fmt.Sprintf("Dust collected after traveling all paths: %s%d%s", u.TextBold, lastOutput, u.TextReset)
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}
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Reference in New Issue
Block a user