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7 changed files with 133 additions and 586 deletions

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@ -85,35 +85,36 @@ func TestPriorityQueue(t *testing.T) {
is := is.New(t)
type elem [2]int
less := func(b, a *elem) bool {
return (*a)[0] < (*b)[0]
less := func(a, b elem) bool {
return a[0] < b[0]
}
pq := aoc.PriorityQueue(less)
pq.Insert(&elem{1, 4})
pq.Insert(&elem{3, 2})
pq.Insert(&elem{2, 3})
pq.Insert(&elem{4, 1})
pq.Enqueue(elem{1, 4})
pq.Enqueue(elem{3, 2})
pq.Enqueue(elem{2, 3})
pq.Enqueue(elem{4, 1})
v := pq.ExtractMin()
is.True(v != nil)
is.Equal(v, &elem{4, 1})
v, ok := pq.Dequeue()
is.True(ok)
is.Equal(v, elem{4, 1})
v = pq.ExtractMin()
is.True(v != nil)
is.Equal(v, &elem{3, 2})
v, ok = pq.Dequeue()
is.True(ok)
is.Equal(v, elem{3, 2})
v = pq.ExtractMin()
is.True(v != nil)
is.Equal(v, &elem{2, 3})
v, ok = pq.Dequeue()
is.True(ok)
is.Equal(v, elem{2, 3})
v = pq.ExtractMin()
is.True(v != nil)
is.Equal(v, &elem{1, 4})
v, ok = pq.Dequeue()
is.True(ok)
is.Equal(v, elem{1, 4})
v = pq.ExtractMin()
is.True(v == nil)
v, ok = pq.Dequeue()
is.True(!ok)
is.Equal(v, elem{})
}
func TestSet(t *testing.T) {
@ -139,7 +140,7 @@ func ExamplePriorityQueue() {
pt int
score int
}
less := func(a, b *memo) bool { return a.score < b.score }
less := func(a, b memo) bool { return b.score < a.score }
adj := map[int][][2]int{
0: {{1, 2}, {2, 6}},
@ -155,10 +156,10 @@ func ExamplePriorityQueue() {
dist := aoc.DefaultMap[int](int(^uint(0) >> 1))
dist.Set(0, 0)
pq.Insert(&memo{0, 0})
pq.Enqueue(memo{0, 0})
for !pq.IsEmpty() {
m := pq.ExtractMin()
m, _ := pq.Dequeue()
u := m.pt
if visited.Has(u) {
@ -174,7 +175,7 @@ func ExamplePriorityQueue() {
if !visited.Has(v) && du+w < dv {
dist.Set(v, du+w)
pq.Insert(&memo{v, du + w})
pq.Enqueue(memo{v, du + w})
}
}
}
@ -194,160 +195,3 @@ func ExamplePriorityQueue() {
// point 5 is 22 steps away.
// point 6 is 19 steps away.
}
func TestStack(t *testing.T) {
is := is.New(t)
s := aoc.Stack(1, 2, 3, 4)
is.True(!s.IsEmpty())
is.Equal(s.Pop(), 4)
is.Equal(s.Pop(), 3)
is.Equal(s.Pop(), 2)
is.Equal(s.Pop(), 1)
is.True(s.IsEmpty())
s.Push(4, 3, 2, 1)
is.True(!s.IsEmpty())
is.Equal(s.Pop(), 1)
is.Equal(s.Pop(), 2)
is.Equal(s.Pop(), 3)
is.Equal(s.Pop(), 4)
is.True(s.IsEmpty())
}
func TestGraph(t *testing.T) {
is := is.New(t)
var adjacencyList = map[int][]int{
2: {3, 5, 1},
1: {2, 4},
3: {6, 2},
4: {1, 5, 7},
5: {2, 6, 8, 4},
6: {3, 0, 9, 5},
7: {4, 8},
8: {5, 9, 7},
9: {6, 0, 8},
}
g := aoc.Graph(aoc.WithAdjacencyList[int, int](adjacencyList))
is.Equal(g.Neighbors(1), []int{2, 4})
is.Equal(map[int][]int(g.AdjacencyList()), adjacencyList)
}
func ExampleFibHeap() {
type memo struct {
pt int
score int
}
less := func(a, b *memo) bool { return (*a).score < (*b).score }
adj := map[int][][2]int{
0: {{1, 2}, {2, 6}},
1: {{3, 5}},
2: {{3, 8}},
3: {{4, 10}, {5, 15}},
4: {{6, 2}},
5: {{6, 6}},
}
pq := aoc.FibHeap(less)
visited := aoc.Set([]int{}...)
dist := aoc.DefaultMap[int](int(^uint(0) >> 1))
dist.Set(0, 0)
pq.Insert(&memo{0, 0})
for !pq.IsEmpty() {
m := pq.ExtractMin()
u := m.pt
if visited.Has(u) {
continue
}
visited.Add(u)
du, _ := dist.Get(u)
for _, edge := range adj[u] {
v, w := edge[0], edge[1]
dv, _ := dist.Get(v)
if !visited.Has(v) && du+w < dv {
dist.Set(v, du+w)
pq.Insert(&memo{v, du + w})
}
}
}
items := dist.Items()
sort.Slice(items, func(i, j int) bool { return items[i].K < items[j].K })
for _, v := range items {
fmt.Printf("point %d is %d steps away.\n", v.K, v.V)
}
// Output:
// point 0 is 0 steps away.
// point 1 is 2 steps away.
// point 2 is 6 steps away.
// point 3 is 7 steps away.
// point 4 is 17 steps away.
// point 5 is 22 steps away.
// point 6 is 19 steps away.
}
func TestFibHeap(t *testing.T) {
is := is.New(t)
type elem [2]int
less := func(a, b *elem) bool {
return (*a)[0] < (*b)[0]
}
pq := aoc.FibHeap(less)
pq.Insert(&elem{1, 4})
pq.Insert(&elem{3, 2})
pq.Insert(&elem{2, 3})
pq.Insert(&elem{4, 1})
v := pq.ExtractMin()
is.True(v != nil)
is.Equal(v, &elem{1, 4})
pq.Insert(&elem{5, 8})
pq.Insert(&elem{6, 7})
pq.Insert(&elem{7, 6})
pq.Insert(&elem{8, 5})
v = pq.ExtractMin()
is.True(v != nil)
is.Equal(v, &elem{2, 3})
v = pq.ExtractMin()
is.True(v != nil)
is.Equal(v, &elem{3, 2})
v = pq.ExtractMin()
is.True(v != nil)
is.Equal(v, &elem{4, 1})
v = pq.ExtractMin()
is.True(v != nil)
is.Equal(v, &elem{5, 8})
m := aoc.FibHeap(less)
m.Insert(&elem{12, 9})
m.Insert(&elem{11, 10})
m.Insert(&elem{10, 11})
m.Insert(&elem{9, 12})
pq.Merge(m)
var keys []int
for !pq.IsEmpty() {
v := pq.ExtractMin()
fmt.Println(v)
keys = append(keys, v[0])
}
is.Equal(keys, []int{6, 7, 8, 9, 10, 11, 12})
}

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@ -29,10 +29,10 @@ func run(scan *bufio.Scanner) (*result, error) {
log("start day 17")
result := result{}
result.valuePT1 = search(m, 1, 3, seenFn)
result.valuePT1 = search(m, 1, 3)
log("result from part 1 = ", result.valuePT1)
result.valuePT2 = search(m, 4, 10, nil)
result.valuePT2 = search(m, 4, 10)
log("result from part 2 = ", result.valuePT2)
return &result, nil
@ -90,7 +90,6 @@ type graph struct {
m Map
target Point
reads int
seenFn func(a position) position
}
// Neighbors returns valid steps from given position. if at target returns none.
@ -119,7 +118,6 @@ func (g *graph) Neighbors(current position) []position {
if forward := current.step(); current.steps < g.max && g.m.Valid(forward.loc) {
nbs = append(nbs, forward)
}
return nbs
}
@ -131,13 +129,12 @@ func (g *graph) Cost(a, b position) int16 {
}
// Potential calculates distance to target
// func (g *graph) Potential(a position) int16 {
// return aoc.ManhattanDistance(a.loc, g.target)
// }
func (g *graph) Potential(a, b position) int16 {
return aoc.ManhattanDistance(a.loc, b.loc)
}
// Target returns true when target reached. receives node and cost.
func (g *graph) Target(a position, c int16) bool {
if a.loc == g.target && a.steps >= g.min && a.steps <= g.max {
func (g *graph) Target(a position) bool {
if a.loc == g.target && a.steps >= g.min {
return true
}
return false
@ -145,79 +142,47 @@ func (g *graph) Target(a position, c int16) bool {
// Seen attempt at simplifying the seen to use horizontal/vertical and no steps.
// It returns correct for part1 but not part 2..
func (g *graph) Seen(a position) position {
if g.seenFn != nil {
return g.seenFn(a)
}
return a
}
// func (g *graph) Seen(a position) position {
// if a.direction == U {
// a.direction = D
// }
// if a.direction == L {
// a.direction = R
// }
// a.steps = 0
// return a
// }
func seenFn(a position) position {
if a.direction == U {
a.direction = D
}
if a.direction == L {
a.direction = R
}
// a.steps = 0
return a
}
func search(m Map, minSteps, maxSteps int8, seenFn func(position) position) int {
func search(m Map, minSteps, maxSteps int8) int {
rows, cols := m.Size()
start := Point{}
target := Point{rows - 1, cols - 1}
g := graph{min: minSteps, max: maxSteps, m: m, target: target, seenFn: seenFn}
g := graph{min: minSteps, max: maxSteps, m: m, target: target}
cost, path := aoc.FindPath[int16, position](&g, position{loc: start}, position{loc: target})
cost, path, closed := aoc.FindPath[int16, position](&g, position{loc: start}, position{loc: target})
log("total map reads = ", g.reads, "cost = ", cost)
printGraph(m, path, closed, g.seenFn)
log("total map reads = ", g.reads)
printGraph(m, path)
return int(cost)
}
// printGraph with the path/cost overlay
func printGraph(m Map, path []position, closed map[position]int16, seenFn func(a position) position) {
// printGraph with the path overlay
func printGraph(m Map, path []position) {
pts := make(map[Point]position, len(path))
for _, pt := range path {
pts[pt.loc] = pt
}
clpt := make(map[position]position, len(closed))
for pt := range closed {
clpt[position{loc: pt.loc, steps: pt.steps}] = pt
}
for r, row := range m {
// if r == 0 {
// for c := range row {
// if c == 0 {
// fmt.Print(" ")
// }
// fmt.Printf("% 5d", c)
// }
// fmt.Println("")
// }
for c := range row {
// if c == 0 {
// fmt.Printf("% 5d", r)
// }
if pt, ok := pts[Point{int16(r), int16(c)}]; ok {
if seenFn != nil {
pt = seenFn(pt)
}
_ = pt
// fmt.Printf("% 5d", closed[pt])
if _, ok := pts[Point{int16(r), int16(c)}]; ok {
fmt.Print("*")
continue
}
// fmt.Print(" ....")
fmt.Print(" ")
fmt.Print(".")
}
fmt.Println("")
}

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@ -28,14 +28,14 @@ func TestExample(t *testing.T) {
is.Equal(result.valuePT2, 94)
}
func TestSolution(t *testing.T) {
is := is.New(t)
scan := bufio.NewScanner(bytes.NewReader(input))
// func TestSolution(t *testing.T) {
// is := is.New(t)
// scan := bufio.NewScanner(bytes.NewReader(input))
result, err := run(scan)
is.NoErr(err)
// result, err := run(scan)
// is.NoErr(err)
t.Log(result)
is.Equal(result.valuePT1, 843)
is.Equal(result.valuePT2, 1017)
}
// t.Log(result)
// is.Equal(result.valuePT1, 843)
// is.Equal(result.valuePT2, 1017)
// }

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@ -186,8 +186,8 @@ func solveWorkflow(parts []part, workflows map[string][]rule) int {
func solveRanges(workflows map[string][]rule) uint {
pq := aoc.PriorityQueue(func(a, b *queue) bool { return false })
pq.Insert(&queue{
pq := aoc.PriorityQueue(func(a, b queue) bool { return false })
pq.Enqueue(queue{
"in",
block{
ranger{1, 4000},
@ -200,9 +200,9 @@ func solveRanges(workflows map[string][]rule) uint {
// var rejected []block
for !pq.IsEmpty() {
current := pq.ExtractMin()
current, _ := pq.Dequeue()
for _, rule := range workflows[current.name] {
next := &queue{name: rule.queue, block: current.block}
next := queue{name: rule.queue, block: current.block}
switch rule.match {
case "x":
@ -223,14 +223,14 @@ func solveRanges(workflows map[string][]rule) uint {
accepted = append(accepted, next.block)
default:
pq.Insert(next)
pq.Enqueue(next)
}
}
}
var sum uint
for _, a := range accepted {
sum += uint((a.x[1] - a.x[0] + 1) * (a.m[1] - a.m[0] + 1) * (a.a[1] - a.a[0] + 1) * (a.s[1] - a.s[0] + 1))
sum += uint((a.x[1]-a.x[0]+1) * (a.m[1]-a.m[0]+1) * (a.a[1]-a.a[0]+1) * (a.s[1]-a.s[0]+1))
}
return sum

102
grids.go
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@ -1,10 +1,5 @@
package aoc
import (
"cmp"
"sort"
)
type Vector struct {
Offset Point[int]
Scale int
@ -63,7 +58,7 @@ func NumPoints(outline []Point[int], borderLength int) int {
type Map[I integer, T any] [][]T
func (m *Map[I, T]) Get(p Point[I]) (Point[I], T, bool) {
func (m *Map[I,T]) Get(p Point[I]) (Point[I], T, bool) {
var zero T
if !m.Valid(p) {
return [2]I{0, 0}, zero, false
@ -71,104 +66,13 @@ func (m *Map[I, T]) Get(p Point[I]) (Point[I], T, bool) {
return p, (*m)[p[0]][p[1]], true
}
func (m *Map[I, T]) Size() (I, I) {
func (m *Map[I,T]) Size() (I, I) {
if m == nil || len(*m) == 0 {
return 0, 0
}
return I(len(*m)), I(len((*m)[0]))
}
func (m *Map[I, T]) Valid(p Point[I]) bool {
func (m *Map[I,T]) Valid(p Point[I]) bool {
rows, cols := m.Size()
return p[0] >= 0 && p[0] < rows && p[1] >= 0 && p[1] < cols
}
type adjacencyList[V any, C comparable] map[C][]V
type graph[V any, W cmp.Ordered, C comparable] map[C]*vertex[V, W]
type graphOption[V any, W cmp.Ordered, C comparable] func(g *graph[V, W, C])
type vertex[V any, W cmp.Ordered] struct {
Value V
Edges edges[V, W]
}
func (v *vertex[V, W]) Neighbors() []V {
var nbs []V
sort.Sort(v.Edges)
for _, e := range v.Edges {
nbs = append(nbs, e.Vertex.Value)
}
return nbs
}
type edge[V any, W cmp.Ordered] struct {
Vertex *vertex[V, W]
Weight W
}
type edges[V any, W cmp.Ordered] []edge[V, W]
func (e edges[V, W]) Len() int { return len(e) }
func (e edges[V, W]) Less(i, j int) bool { return e[i].Weight < e[j].Weight }
func (e edges[V, W]) Swap(i, j int) { e[i], e[j] = e[j], e[i] }
func Graph[V any, W cmp.Ordered, C comparable](opts ...graphOption[V, W, C]) *graph[V, W, C] {
g := make(graph[V, W, C])
for _, opt := range opts {
opt(&g)
}
return &g
}
func (g *graph[V, W, C]) AddVertex(id C, value V) {
(*g)[id] = &vertex[V,W]{Value: value}
}
func (g *graph[V, W, C]) AddEdge(from, to C, w W) {
if g == nil {
return
}
if _, ok := (*g)[from]; !ok {
return
}
if _, ok := (*g)[to]; !ok {
return
}
(*g)[from].Edges = append((*g)[from].Edges, edge[V,W]{(*g)[to], w})
}
func (g *graph[V, W, C]) Neighbors(v C) []V {
if g == nil {
return nil
}
return (*g)[v].Neighbors()
}
func (g *graph[V, W, C]) AdjacencyList() adjacencyList[V, C] {
m := make(map[C][]V)
for id, v := range *g {
if len(v.Edges) == 0 {
continue
}
m[id] = v.Neighbors()
}
return m
}
func WithAdjacencyList[W cmp.Ordered, C comparable](list adjacencyList[C, C]) graphOption[C, W, C] {
var zeroW W
return func(g *graph[C, W, C]) {
for vertex, edges := range list {
if _, ok := (*g)[vertex]; !ok {
g.AddVertex(vertex, vertex)
}
// add edges to vertex
for _, edge := range edges {
// add edge as vertex, if not added
if _, ok := (*g)[edge]; !ok {
g.AddVertex(edge, edge)
}
g.AddEdge(vertex, edge, zeroW) // no weights in this adjacency list
}
}
}
}
// func GraphFromMap()

View File

@ -2,70 +2,26 @@ package aoc
import (
"bufio"
"flag"
"fmt"
"log"
"os"
"path/filepath"
"runtime"
"runtime/pprof"
"strings"
"time"
)
var cpuprofile = flag.String("cpuprofile", "", "write cpu profile to `file`")
var memprofile = flag.String("memprofile", "", "write memory profile to `file`")
func Runner[R any, F func(*bufio.Scanner) (R, error)](run F) (R, error) {
if len(os.Args) < 2 {
if len(os.Args) != 2 {
Log("Usage:", filepath.Base(os.Args[0]), "FILE")
os.Exit(22)
}
inputFilename := os.Args[1]
os.Args = append(os.Args[:1], os.Args[2:]...)
flag.Parse()
Log(cpuprofile, memprofile, *cpuprofile, *memprofile)
if *cpuprofile != "" {
Log("enabled cpu profile")
f, err := os.Create(*cpuprofile)
if err != nil {
log.Fatal("could not create CPU profile: ", err)
}
defer f.Close() // error handling omitted for example
Log("write cpu profile to", f.Name())
if err := pprof.StartCPUProfile(f); err != nil {
log.Fatal("could not start CPU profile: ", err)
}
defer pprof.StopCPUProfile()
}
if *memprofile != "" {
Log("enabled mem profile")
defer func() {
f, err := os.Create(*memprofile)
if err != nil {
log.Fatal("could not create memory profile: ", err)
}
Log("write mem profile to", f.Name())
defer f.Close() // error handling omitted for example
runtime.GC() // get up-to-date statistics
if err := pprof.WriteHeapProfile(f); err != nil {
log.Fatal("could not write memory profile: ", err)
}
}()
}
input, err := os.Open(inputFilename)
input, err := os.Open(os.Args[1])
if err != nil {
Log(err)
os.Exit(1)
}
scan := bufio.NewScanner(input)
return run(scan)
}

244
search.go
View File

@ -1,13 +1,12 @@
package aoc
import (
"math/bits"
"sort"
)
type priorityQueue[T any] struct {
elems []*T
less func(a, b *T) bool
elems []T
less func(a, b T) bool
maxDepth int
totalEnqueue int
totalDequeue int
@ -17,10 +16,10 @@ type priorityQueue[T any] struct {
// less is the function for sorting. reverse a and b to reverse the sort.
// T is the item
// U is a slice of T
func PriorityQueue[T any](less func(a, b *T) bool) *priorityQueue[T] {
func PriorityQueue[T any](less func(a, b T) bool) *priorityQueue[T] {
return &priorityQueue[T]{less: less}
}
func (pq *priorityQueue[T]) Insert(elem *T) {
func (pq *priorityQueue[T]) Enqueue(elem T) {
pq.totalEnqueue++
pq.elems = append(pq.elems, elem)
@ -29,65 +28,35 @@ func (pq *priorityQueue[T]) Insert(elem *T) {
func (pq *priorityQueue[T]) IsEmpty() bool {
return len(pq.elems) == 0
}
func (pq *priorityQueue[T]) ExtractMin() *T {
func (pq *priorityQueue[T]) Dequeue() (T, bool) {
pq.totalDequeue++
var elem *T
var elem T
if pq.IsEmpty() {
return elem
return elem, false
}
sort.Slice(pq.elems, func(i, j int) bool { return pq.less(pq.elems[j], pq.elems[i]) })
sort.Slice(pq.elems, func(i, j int) bool { return pq.less(pq.elems[i], pq.elems[j]) })
pq.elems, elem = pq.elems[:len(pq.elems)-1], pq.elems[len(pq.elems)-1]
return elem
}
type stack[T any] []T
func Stack[T any](a ...T) *stack[T] {
var s stack[T] = a
return &s
}
func (s *stack[T]) Push(a ...T) {
if s == nil {
return
}
*s = append(*s, a...)
}
func (s *stack[T]) IsEmpty() bool {
return s == nil || len(*s) == 0
}
func (s *stack[T]) Pop() T {
var a T
if s.IsEmpty() {
return a
}
a, *s = (*s)[len(*s)-1], (*s)[:len(*s)-1]
return a
return elem, true
}
// ManhattanDistance the distance between two points measured along axes at right angles.
func ManhattanDistance[T integer](a, b Point[T]) T {
return ABS(a[0]-b[0]) + ABS(a[1]-b[1])
return ABS(a[1]-b[1]) + ABS(a[0]-b[0])
}
type pather[C number, N comparable] interface {
// Neighbors returns all neighbors to node N that should be considered next.
Neighbors(N) []N
// Cost returns
Cost(a, b N) C
// Target returns true when target reached. receives node and cost.
Target(N, C) bool
Potential(a, b N) C
// OPTIONAL:
// Add heuristic for running as A* search.
// Potential(N) C
// Seen modify value used by seen pruning.
// Seen(N) N
// Target returns true if target reached.
// Target(N) bool
}
// FindPath uses the A* path finding algorithem.
@ -98,18 +67,9 @@ type pather[C number, N comparable] interface {
//
// start, end are nodes that dileniate the start and end of the search path.
// The returned values are the calculated cost and the path taken from start to end.
func FindPath[C integer, N comparable](g pather[C, N], start, end N) (C, []N, map[N]C) {
func FindPath[C integer, N comparable](g pather[C, N], start, end N) (C, []N) {
var zero C
var seenFn = func(a N) N { return a }
if s, ok := g.(interface{ Seen(N) N }); ok {
seenFn = s.Seen
}
var potentialFn = func(N) C { var zero C; return zero }
if p, ok := g.(interface{ Potential(N) C }); ok {
potentialFn = p.Potential
}
closed := make(map[N]bool)
type node struct {
cost C
@ -118,7 +78,7 @@ func FindPath[C integer, N comparable](g pather[C, N], start, end N) (C, []N, ma
position N
}
newPath := func(n *node) []N {
NewPath := func(n *node) []N {
var path []N
for n.parent != nil {
path = append(path, n.position)
@ -130,143 +90,61 @@ func FindPath[C integer, N comparable](g pather[C, N], start, end N) (C, []N, ma
return path
}
less := func(a, b *node) bool {
return a.cost+a.potential < b.cost+b.potential
less := func(a, b node) bool {
return b.cost+b.potential < a.cost+a.potential
}
closed := make(map[N]C)
open := FibHeap(less)
pq := PriorityQueue(less)
pq.Enqueue(node{position: start})
closed[start] = false
open.Insert(&node{position: start, potential: potentialFn(start)})
closed[start] = zero
defer func() {
Log("queue max depth = ", pq.maxDepth, "total enqueue = ", pq.totalEnqueue, "total dequeue = ", pq.totalDequeue)
}()
for !open.IsEmpty() {
current := open.ExtractMin()
for _, nb := range g.Neighbors(current.position) {
next := &node{
position: nb,
parent: current,
cost: g.Cost(current.position, nb) + current.cost,
potential: potentialFn(nb),
var seenFn = func(a N) N { return a }
if s, ok := g.(interface{ Seen(N) N }); ok {
seenFn = s.Seen
}
var targetFn = func(a N) bool { return true }
if s, ok := g.(interface{ Target(N) bool }); ok {
targetFn = s.Target
}
for !pq.IsEmpty() {
current, _ := pq.Dequeue()
cost, potential, n := current.cost, current.potential, current.position
seen := seenFn(n)
if closed[seen] {
continue
}
closed[seen] = true
if cost > 0 && potential == zero && targetFn(current.position) {
return cost, NewPath(&current)
}
for _, nb := range g.Neighbors(n) {
seen := seenFn(nb)
cost, ok := closed[seen]
if !ok || next.cost < cost {
open.Insert(next)
closed[seen] = next.cost
if closed[seen] {
continue
}
if next.potential == zero && g.Target(next.position, next.cost) {
return next.cost, newPath(next), closed
cost := g.Cost(n, nb) + current.cost
nextPath := node{
position: nb,
parent: &current,
cost: cost,
potential: g.Potential(nb, end),
}
// check if path is in open list
if _, open := closed[seen]; !open {
pq.Enqueue(nextPath)
closed[seen] = false // add to open list
}
}
}
return zero, nil, closed
return zero, nil
}
type fibTree[T any] struct {
value *T
parent *fibTree[T]
child []*fibTree[T]
}
func (t *fibTree[T]) addAtEnd(n *fibTree[T]) {
n.parent = t
t.child = append(t.child, n)
}
type fibHeap[T any] struct {
trees []*fibTree[T]
least *fibTree[T]
count uint
less func(a, b *T) bool
}
func FibHeap[T any](less func(a, b *T) bool) *fibHeap[T] {
return &fibHeap[T]{less: less}
}
func (h *fibHeap[T]) GetMin() *T {
return h.least.value
}
func (h *fibHeap[T]) IsEmpty() bool { return h.least == nil }
func (h *fibHeap[T]) Insert(v *T) {
ntree := &fibTree[T]{value: v}
h.trees = append(h.trees, ntree)
if h.least == nil || h.less(v, h.least.value) {
h.least = ntree
}
h.count++
}
func (h *fibHeap[T]) ExtractMin() *T {
smallest := h.least
if smallest != nil {
// Remove smallest from root trees.
for i := range h.trees {
pos := h.trees[i]
if pos == smallest {
h.trees[i] = h.trees[len(h.trees)-1]
h.trees = h.trees[:len(h.trees)-1]
break
}
}
// Add children to root
h.trees = append(h.trees, smallest.child...)
smallest.child = smallest.child[:0]
h.least = nil
if len(h.trees) > 0 {
h.consolidate()
}
h.count--
return smallest.value
}
return nil
}
func (h *fibHeap[T]) consolidate() {
aux := make([]*fibTree[T], bits.Len(h.count))
for _, x := range h.trees {
order := len(x.child)
// consolidate the larger roots under smaller roots of same order until we have at most one tree per order.
for aux[order] != nil {
y := aux[order]
if h.less(y.value, x.value) {
x, y = y, x
}
x.addAtEnd(y)
aux[order] = nil
order++
}
aux[order] = x
}
h.trees = h.trees[:0]
// move ordered trees to root and find least node.
for _, k := range aux {
if k != nil {
k.parent = nil
h.trees = append(h.trees, k)
if h.least == nil || h.less(k.value, h.least.value) {
h.least = k
}
}
}
}
func (h *fibHeap[T]) Merge(a *fibHeap[T]) {
h.trees = append(h.trees, a.trees...)
h.count += a.count
h.consolidate()
}
// func (h *fibHeap[T]) Find(n *T) *fibTree[T] {
// }