2023 Day 21 Complete

This commit is contained in:
Brian Buller 2023-12-26 10:25:53 -06:00
parent b393c79247
commit 3d42462d4c
4 changed files with 230 additions and 169 deletions

View File

@ -1,194 +1,85 @@
package main package main
import ( import (
"container/list"
"fmt" "fmt"
"image"
h "git.bullercodeworks.com/brian/adventofcode/helpers" "os"
"strings"
) )
func main() { func main() {
inp := h.StdinToStringSlice() data, _ := os.ReadFile("input")
part1(inp) answer := solution(data, 64)
fmt.Println()
part2(inp)
}
func part1(input []string) {
m := h.StringSliceToCoordByteMap(input)
start, _ := m.FindFirst('S')
m.Put(start, '.')
result := []h.Coordinate{start}
for i := 0; i < 64; i++ {
result = findNext(&m, result)
}
fmt.Println("# Part 1") fmt.Println("# Part 1")
fmt.Println(len(result)) fmt.Println(answer[0])
}
// 253370351984188 is too low
func part2(input []string) {
m := h.StringSliceToCoordByteMap(input)
start, _ := m.FindFirst('S')
m.Put(start, '.')
steps := 26501365
p := make([]int, 3)
size := len(input)
half := size / 2
fmt.Println("Getting Plots: p[0]")
p[0], _ = getPlots(&m, half, 5)
fmt.Println("Getting Plots: p[1]")
m = h.StringSliceToCoordByteMap(input)
p[1], _ = getPlots(&m, half+size, 5)
fmt.Println("Getting Plots: p[2]")
m = h.StringSliceToCoordByteMap(input)
p[2], _ = getPlots(&m, half+2*size, 5)
a := (p[2] + p[0] - 2*p[1]) / 2
b := p[1] - p[0] - a
c := p[0]
n := steps / size
result := a*n*n + b*n + c
fmt.Println("# Part 2") fmt.Println("# Part 2")
fmt.Println(result) fmt.Println(answer[1])
} }
var visited map[string]bool func solution(data []byte, total_steps int) []int {
lines := strings.Split(strings.TrimSpace(string(data)), "\n")
func getPlots(m *h.CoordByteMap, steps int, factor int) (int, error) { q := list.New()
sx, sy := m.ColCount(), m.RowCount() symbols := map[image.Point]string{}
l := sy for y, line := range lines {
expandMap(m, factor) l := strings.TrimSpace(line)
sx = l * (factor / 2) //fmt.Println(len(s))
sy = l * (factor / 2) for x, r := range l {
visited = make(map[string]bool) symbols[image.Point{x, y}] = string(r)
return len(nextStep(sx, sy, 0, steps, m)), nil if r == 'S' {
} q.PushBack(image.Point{x, y})
}
func isPlot(m *h.CoordByteMap, x, y int) bool {
return m.Get(h.Coordinate{X: x, Y: y}) == '.'
}
func nextStep(x, y, step, max int, m *h.CoordByteMap) []h.Coordinate {
var acc []h.Coordinate
var key = fmt.Sprintf("%d;%d;%d", x, y, step)
if _, ok := visited[key]; ok {
return []h.Coordinate{}
} else {
visited[key] = true
}
if step == max {
return []h.Coordinate{{X: x, Y: y}}
}
if x > 0 && isPlot(m, x-1, y) {
acc = append(acc, nextStep(x-1, y, step+1, max, m)...)
}
if x < m.ColCount() && isPlot(m, x+1, y) {
acc = append(acc, nextStep(x, y-1, step+1, max, m)...)
}
if y > 0 && isPlot(m, x, y-1) {
acc = append(acc, nextStep(x, y-1, step+1, max, m)...)
}
if y < m.RowCount() && isPlot(m, x, y+1) {
acc = append(acc, nextStep(x, y+1, step+1, max, m)...)
}
return acc
}
func expandMap(m *h.CoordByteMap, factor int) {
stx, edx := m.TLX, m.BRX
for f := 1; f < factor; f++ {
for x := stx; x <= edx; x++ {
col := m.GetCol(x)
m.AddCol(col)
}
sty, edy := m.TLY, m.BRY
for y := sty; y <= edy; y++ {
row := m.GetRow(y)
m.AddRow(row)
} }
} }
}
func part2BruteForce(input []string) { steps := 0
// Brute force just isn't going to cut it... total := 26501365
m := h.StringSliceToCoordByteMap(input) part_1 := 0
m.StringEmptyIsSpace = true part_2 := 0
m.StringEmptyByte = '.'
seen := make(map[h.Coordinate]bool)
start, _ := m.FindFirst('S')
m.Put(start, '.')
result := []h.Coordinate{start}
steps := 26501365
for i := 0; i < steps; i++ {
fmt.Println(h.CLEAR_SCREEN)
fmt.Printf("%d/%d (%f)\n", i, steps, float64(i)/float64(steps))
seen, result = findNextInfiniteRepeat(&m, seen, result)
if i == 100 {
break
}
}
fmt.Println("# Part 2")
fmt.Println(len(result))
for i := range result {
m.Put(result[i], 'O')
}
fmt.Println(m)
// It's making a diamond shape...
}
func findNext(m *h.CoordByteMap, curr []h.Coordinate) []h.Coordinate { directions := []image.Point{
var result []h.Coordinate {-1, 0}, {0, -1}, {0, 1}, {1, 0},
for _, c := range curr { }
for _, tst := range []h.Coordinate{
c.North(), c.East(), c.South(), c.West(), polynomial := make([]int, 0)
} { for steps < total {
if m.ContainsCoord(tst) && m.Get(tst) == '.' { new_Q := list.New()
var contains bool visited := make(map[image.Point]bool)
for i := range result {
if result[i].Equals(tst) { for q.Len() > 0 {
contains = true element := q.Front()
break val := element.Value.(image.Point)
q.Remove(element)
x, y := val.X, val.Y
for _, d := range directions {
newPos := image.Point{x + d.X, y + d.Y}
ref := image.Point{((newPos.Y % len(lines)) + len(lines)) % len(lines), ((newPos.X % len(lines)) + len(lines)) % len(lines)}
if symbols[ref] != "#" {
if _, ok := visited[newPos]; !ok {
visited[newPos] = true
new_Q.PushBack(newPos)
} }
} }
if !contains {
result = append(result, tst)
}
} }
} }
} steps += 1
return result q = new_Q //update queue
} if steps%(len(lines)) == total%len(lines) {
polynomial = append(polynomial, len(visited))
if len(polynomial) == 3 {
p0 := polynomial[0]
p1 := polynomial[1] - polynomial[0]
p2 := polynomial[2] - polynomial[1]
func findNextInfiniteRepeat(m *h.CoordByteMap, seen map[h.Coordinate]bool, curr []h.Coordinate) (map[h.Coordinate]bool, []h.Coordinate) { part_2 = p0 + (p1 * (total / len(lines))) + ((total/len(lines))*((total/len(lines))-1)/2)*(p2-p1)
var result []h.Coordinate break
for _, c := range curr {
for _, tst := range []h.Coordinate{
c.North(), c.East(), c.South(), c.West(),
} {
if seen[tst] {
continue
}
wrkX, wrkY := tst.X, tst.Y
for wrkX < m.TLX {
wrkX += m.BRX
}
for wrkY < m.TLY {
wrkY += m.BRY
}
wrk := h.Coordinate{X: (wrkX % m.BRX), Y: (wrkY % m.BRY)}
if m.Get(wrk) == '.' {
var contains bool
for i := range result {
if result[i].Equals(tst) {
contains = true
break
}
}
if !contains {
result = append(result, tst)
seen[tst] = true
}
} }
} }
if steps == total_steps {
part_1 = len(visited)
}
} }
return seen, result
return []int{part_1, part_2}
} }

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@ -17,6 +17,10 @@ type CoordByteMap struct {
// Options for the 'String' method // Options for the 'String' method
StringEmptyIsSpace bool StringEmptyIsSpace bool
StringEmptyByte byte StringEmptyByte byte
// If 'Repeats' is true, then any coordinate request will be
// modded by BRX/BRY
Repeats bool
} }
func NewCoordByteMap() CoordByteMap { func NewCoordByteMap() CoordByteMap {
@ -49,6 +53,9 @@ func (m *CoordByteMap) ColCount() int {
return m.BRX - m.TLX return m.BRX - m.TLX
} }
func (m *CoordByteMap) GetRow(y int) []byte { func (m *CoordByteMap) GetRow(y int) []byte {
if m.Repeats {
y = (y + m.BRY) % m.BRY
}
var resp []byte var resp []byte
for x := m.TLX; x <= m.BRX; x++ { for x := m.TLX; x <= m.BRX; x++ {
resp = append(resp, m.Get(Coordinate{X: x, Y: y})) resp = append(resp, m.Get(Coordinate{X: x, Y: y}))
@ -56,6 +63,9 @@ func (m *CoordByteMap) GetRow(y int) []byte {
return resp return resp
} }
func (m *CoordByteMap) GetCol(x int) []byte { func (m *CoordByteMap) GetCol(x int) []byte {
if m.Repeats {
x = (x + m.BRX) % m.BRX
}
var resp []byte var resp []byte
for y := m.TLY; y <= m.BRY; y++ { for y := m.TLY; y <= m.BRY; y++ {
resp = append(resp, m.Get(Coordinate{X: x, Y: y})) resp = append(resp, m.Get(Coordinate{X: x, Y: y}))
@ -76,10 +86,18 @@ func (m *CoordByteMap) AddCol(col []byte) {
} }
func (m *CoordByteMap) GetPos(x, y int) byte { func (m *CoordByteMap) GetPos(x, y int) byte {
if m.Repeats {
x = (x + m.BRX) % m.BRX
y = (y + m.BRY) % m.BRY
}
return m.Get(Coordinate{X: x, Y: y}) return m.Get(Coordinate{X: x, Y: y})
} }
func (m *CoordByteMap) Get(pos Coordinate) byte { func (m *CoordByteMap) Get(pos Coordinate) byte {
if m.Repeats {
pos.X = (pos.X + m.BRX) % m.BRX
pos.Y = (pos.Y + m.BRY) % m.BRY
}
if v, ok := m.Field[pos]; ok { if v, ok := m.Field[pos]; ok {
return v return v
} }
@ -87,6 +105,10 @@ func (m *CoordByteMap) Get(pos Coordinate) byte {
} }
func (m *CoordByteMap) Opt(pos Coordinate, def byte) byte { func (m *CoordByteMap) Opt(pos Coordinate, def byte) byte {
if m.Repeats {
pos.X = (pos.X + m.BRX) % m.BRX
pos.Y = (pos.Y + m.BRY) % m.BRY
}
if v, ok := m.Field[pos]; ok { if v, ok := m.Field[pos]; ok {
return v return v
} }
@ -110,6 +132,10 @@ func (m *CoordByteMap) Put(pos Coordinate, val byte) {
} }
func (m *CoordByteMap) Delete(pos Coordinate) { func (m *CoordByteMap) Delete(pos Coordinate) {
if m.Repeats {
pos.X = (pos.X + m.BRX) % m.BRX
pos.Y = (pos.Y + m.BRY) % m.BRY
}
delete(m.Field, pos) delete(m.Field, pos)
} }
@ -135,6 +161,10 @@ func (m *CoordByteMap) ToByteSlices() [][]byte {
// ContainsCoord returns true if the passed coordinate is within the bounds // ContainsCoord returns true if the passed coordinate is within the bounds
// of the map // of the map
func (m *CoordByteMap) ContainsCoord(c Coordinate) bool { func (m *CoordByteMap) ContainsCoord(c Coordinate) bool {
if m.Repeats {
c.X = (c.X + m.BRX) % m.BRX
c.Y = (c.Y + m.BRY) % m.BRY
}
return c.X >= m.TLX && c.X <= m.BRX && return c.X >= m.TLX && c.X <= m.BRX &&
c.Y >= m.TLY && c.Y <= m.BRY c.Y >= m.TLY && c.Y <= m.BRY
} }

62
helpers/priorityQueue.go Normal file
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@ -0,0 +1,62 @@
package aoc
type PriorityQueue[T comparable] struct {
items []T
comparator func(a, b T) int
}
func NewPriorityQueue[T comparable](comparator func(a, b T) int) PriorityQueue[T] {
return PriorityQueue[T]{comparator: comparator}
}
func (pq *PriorityQueue[T]) Push(item T) {
pq.items = append(pq.items, item)
pq.heapifyUp(len(pq.items) - 1)
}
func (pq *PriorityQueue[T]) Pop() T {
top := pq.items[0]
lastIndex := len(pq.items) - 1
pq.items[0], pq.items[lastIndex] = pq.items[lastIndex], pq.items[0]
pq.items = pq.items[:lastIndex]
pq.heapifyDown(0)
return top
}
func (pq *PriorityQueue[T]) Peek() T {
return pq.items[0]
}
func (pq *PriorityQueue[T]) Len() int {
return len(pq.items)
}
func (pq *PriorityQueue[T]) IsEmpty() bool {
return len(pq.items) == 0
}
func (pq *PriorityQueue[T]) IsNotEmpty() bool {
return !pq.IsEmpty()
}
func (pq *PriorityQueue[T]) heapifyUp(index int) {
for index > 0 {
parentIndex := (index - 1) / 2
if pq.comparator(pq.items[index], pq.items[parentIndex]) < 0 {
pq.items[index], pq.items[parentIndex] = pq.items[parentIndex], pq.items[index]
index = parentIndex
} else {
break
}
}
}
func (pq *PriorityQueue[T]) heapifyDown(index int) {
for {
leftChild, rightChild, smallest := 2*index+1, 2*index+2, index
if leftChild < len(pq.items) && pq.comparator(pq.items[leftChild], pq.items[smallest]) < 0 {
smallest = leftChild
}
if rightChild < len(pq.items) && pq.comparator(pq.items[rightChild], pq.items[smallest]) < 0 {
smallest = rightChild
}
if smallest != index {
pq.items[index], pq.items[smallest] = pq.items[smallest], pq.items[index]
index = smallest
} else {
break
}
}
}

78
helpers/queue.go Normal file
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@ -0,0 +1,78 @@
package aoc
type Queue[T comparable] struct {
items []T
}
func NewQueue[T comparable](items []T) *Queue[T] {
return &Queue[T]{
items: items,
}
}
func (q *Queue[T]) Len() int {
return len(q.items)
}
func (q *Queue[T]) Push(item T) {
q.items = append(q.items, item)
}
func (q *Queue[T]) Pop() T {
var x T
x, q.items = q.items[len(q.items)-1], q.items[:len(q.items)-1]
return x
}
func (q *Queue[T]) Unshift(item T) {
q.items = append([]T{item}, q.items...)
}
func (q *Queue[T]) Shift() T {
var x T
x, q.items = q.items[0], q.items[1:]
return x
}
func (q *Queue[T]) Append(items []T) {
q.items = append(q.items, items...)
}
func (q *Queue[T]) Copy() *Queue[T] {
ret := &Queue[T]{
items: make([]T, len(q.items)),
}
copy(ret.items, q.items)
return ret
}
func (q *Queue[T]) Cut(at, count int) []T {
ret := q.items[at : at+count]
q.items = append(q.items[:at], q.items[at+count:]...)
return ret
}
func (q *Queue[T]) Delete(item T) {
for i := range q.items {
if q.items[i] == item {
q.items = append(q.items[:i], q.items[i+1:]...)
return
}
}
}
func (q *Queue[T]) Expand(at, by int) {
q.items = append(q.items[:at], append(make([]T, by), q.items[at:]...)...)
}
func (q *Queue[T]) Extend(by int) {
q.items = append(q.items, make([]T, by)...)
}
func (q *Queue[T]) FilterInPlace(keep func(item T) bool) {
n := 0
for _, x := range q.items {
if keep(x) {
q.items[n] = x
n++
}
}
q.items = q.items[:n]
}
func (q *Queue[T]) Insert(item T, location int) {
q.InsertVector([]T{item}, location)
}
func (q *Queue[T]) InsertVector(items []T, location int) {
q.items = append(q.items[:location], append(items, q.items[location:]...)...)
}