chore(day23): solution for day23 pt1/pt2

aoc_test.go

@@ -9,66 +9,6 @@ import (
 	aoc "go.sour.is/advent-of-code"
 )
 
-func TestReverse(t *testing.T) {
-	is := is.New(t)
-
-	is.Equal(aoc.Reverse([]int{1, 2, 3, 4}), []int{4, 3, 2, 1})
-}
-
-func TestLCM(t *testing.T) {
-	is := is.New(t)
-
-	is.Equal(aoc.LCM([]int{}...), 0)
-	is.Equal(aoc.LCM(5), 5)
-	is.Equal(aoc.LCM(5, 3), 15)
-	is.Equal(aoc.LCM(5, 3, 2), 30)
-}
-
-func TestReadStringToInts(t *testing.T) {
-	is := is.New(t)
-
-	is.Equal(aoc.ReadStringToInts([]string{"1", "2", "3"}), []int{1, 2, 3})
-}
-
-func TestRepeat(t *testing.T) {
-	is := is.New(t)
-
-	is.Equal(aoc.Repeat(5, 3), []int{5, 5, 5})
-}
-
-func TestPower2(t *testing.T) {
-	is := is.New(t)
-
-	is.Equal(aoc.Power2(0), 1)
-	is.Equal(aoc.Power2(1), 2)
-	is.Equal(aoc.Power2(2), 4)
-}
-
-func TestABS(t *testing.T) {
-	is := is.New(t)
-
-	is.Equal(aoc.ABS(1), 1)
-	is.Equal(aoc.ABS(0), 0)
-	is.Equal(aoc.ABS(-1), 1)
-}
-
-func TestTranspose(t *testing.T) {
-	is := is.New(t)
-
-	is.Equal(
-		aoc.Transpose(
-			[][]int{
-				{1, 1},
-				{0, 0},
-				{1, 1},
-			},
-		),
-		[][]int{
-			{1, 0, 1},
-			{1, 0, 1},
-		},
-	)
-}
 
 func TestList(t *testing.T) {
 	is := is.New(t)
@@ -85,62 +25,44 @@ func TestPriorityQueue(t *testing.T) {
 	is := is.New(t)
 
 	type elem [2]int
-	less := func(a, b elem) bool {
-		return a[0] < b[0]
+	less := func(b, a *elem) bool {
+		return (*a)[0] < (*b)[0]
 	}
 
 	pq := aoc.PriorityQueue(less)
 
-	pq.Enqueue(elem{1, 4})
-	pq.Enqueue(elem{3, 2})
-	pq.Enqueue(elem{2, 3})
-	pq.Enqueue(elem{4, 1})
+	pq.Insert(&elem{1, 4})
+	pq.Insert(&elem{3, 2})
+	pq.Insert(&elem{2, 3})
+	pq.Insert(&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{4, 1})
 
-	v, ok = pq.Dequeue()
-	is.True(ok)
-	is.Equal(v, elem{3, 2})
+	v = pq.ExtractMin()
+	is.True(v != nil)
+	is.Equal(v, &elem{3, 2})
 
-	v, ok = pq.Dequeue()
-	is.True(ok)
-	is.Equal(v, elem{2, 3})
+	v = pq.ExtractMin()
+	is.True(v != nil)
+	is.Equal(v, &elem{2, 3})
 
-	v, ok = pq.Dequeue()
-	is.True(ok)
-	is.Equal(v, elem{1, 4})
+	v = pq.ExtractMin()
+	is.True(v != nil)
+	is.Equal(v, &elem{1, 4})
 
-	v, ok = pq.Dequeue()
-	is.True(!ok)
-	is.Equal(v, elem{})
+	v = pq.ExtractMin()
+	is.True(v == nil)
 }
 
-func TestSet(t *testing.T) {
-	is := is.New(t)
-
-	s := aoc.Set(1, 2, 3)
-	is.True(!s.Has(0))
-	is.True(s.Has(1))
-	is.True(s.Has(2))
-	is.True(s.Has(3))
-	is.True(!s.Has(4))
-
-	s.Add(4)
-	is.True(s.Has(4))
-
-	items := s.Items()
-	sort.Ints(items)
-	is.Equal(items, []int{1, 2, 3, 4})
-}
 
 func ExamplePriorityQueue() {
 	type memo struct {
 		pt    int
 		score int
 	}
-	less := func(a, b memo) bool { return b.score < a.score }
+	less := func(a, b *memo) bool { return a.score < b.score }
 
 	adj := map[int][][2]int{
 		0: {{1, 2}, {2, 6}},
@@ -156,10 +78,10 @@ func ExamplePriorityQueue() {
 	dist := aoc.DefaultMap[int](int(^uint(0) >> 1))
 
 	dist.Set(0, 0)
-	pq.Enqueue(memo{0, 0})
+	pq.Insert(&memo{0, 0})
 
 	for !pq.IsEmpty() {
-		m, _ := pq.Dequeue()
+		m := pq.ExtractMin()
 
 		u := m.pt
 		if visited.Has(u) {
@@ -175,7 +97,7 @@ func ExamplePriorityQueue() {
 
 			if !visited.Has(v) && du+w < dv {
 				dist.Set(v, du+w)
-				pq.Enqueue(memo{v, du + w})
+				pq.Insert(&memo{v, du + w})
 			}
 		}
 	}
@@ -195,3 +117,164 @@ func ExamplePriorityQueue() {
 	// point 5 is 22 steps away.
 	// point 6 is 19 steps away.
 }
+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{1, 99})
+	m.Insert(&elem{12, 9})
+	m.Insert(&elem{11, 10})
+	m.Insert(&elem{10, 11})
+	m.Insert(&elem{9, 12})
+
+	pq.Merge(m)
+
+	v = pq.Find(func(t *elem) bool {
+		return (*t)[0] == 6
+	})
+	is.Equal(v, &elem{6, 7})
+
+	v = pq.Find(func(t *elem) bool {
+		return (*t)[0] == 12
+	})
+	is.Equal(v, &elem{12, 9})
+
+	v = pq.ExtractMin()
+	is.True(v != nil)
+	is.Equal(v, &elem{1, 99})
+
+	pq.DecreaseKey(
+		func(t *elem) bool { return t[0] == 12 },
+		func(t *elem) { t[0] = 3 },
+	)
+
+	v = pq.ExtractMin()
+	is.True(v != nil)
+	is.Equal(v, &elem{3, 9})
+
+	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})
+}

day17/main.go

@@ -29,10 +29,10 @@ func run(scan *bufio.Scanner) (*result, error) {
 	log("start day 17")
 
 	result := result{}
-	result.valuePT1 = search(m, 1, 3)
+	result.valuePT1 = search(m, 1, 3, seenFn)
 	log("result from part 1 = ", result.valuePT1)
 
-	result.valuePT2 = search(m, 4, 10)
+	result.valuePT2 = search(m, 4, 10, nil)
 	log("result from part 2 = ", result.valuePT2)
 
 	return &result, nil
@@ -90,6 +90,7 @@ 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.
@@ -118,6 +119,7 @@ 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
 }
 
@@ -129,12 +131,13 @@ func (g *graph) Cost(a, b position) int16 {
 }
 
 // Potential calculates distance to target
-func (g *graph) Potential(a, b position) int16 {
-	return aoc.ManhattanDistance(a.loc, b.loc)
-}
+// func (g *graph) Potential(a position) int16 {
+// 	return aoc.ManhattanDistance(a.loc, g.target)
+// }
 
-func (g *graph) Target(a position) bool {
-	if a.loc == g.target && a.steps >= g.min {
+// 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 {
 		return true
 	}
 	return false
@@ -142,47 +145,79 @@ func (g *graph) Target(a position) 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 a.direction == U {
-// 		a.direction = D
-// 	}
-// 	if a.direction == L {
-// 		a.direction = R
-// 	}
-// 	a.steps = 0
-// 	return a
-// }
+func (g *graph) Seen(a position) position {
+	if g.seenFn != nil {
+		return g.seenFn(a)
+	}
+	return a
+}
 
-func search(m Map, minSteps, maxSteps int8) int {
+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 {
 	rows, cols := m.Size()
 	start := Point{}
 	target := Point{rows - 1, cols - 1}
 
-	g := graph{min: minSteps, max: maxSteps, m: m, target: target}
-	cost, path := aoc.FindPath[int16, position](&g, position{loc: start}, position{loc: target})
+	g := graph{min: minSteps, max: maxSteps, m: m, target: target, seenFn: seenFn}
 
-	log("total map reads = ", g.reads)
-	printGraph(m, path)
+	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)
 
 	return int(cost)
 }
 
-// printGraph with the path overlay
-func printGraph(m Map, path []position) {
+// printGraph with the path/cost overlay
+func printGraph(m Map, path []position, closed map[position]int16, seenFn func(a position) 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 _, ok := pts[Point{int16(r), int16(c)}]; ok {
+			// 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])
 				fmt.Print("*")
 
 				continue
 			}
 
-			fmt.Print(".")
+			// fmt.Print(" ....")
+			fmt.Print(" ")
 		}
 		fmt.Println("")
 	}

day17/main_test.go

@@ -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)
+}

day19/main.go

@@ -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.Enqueue(queue{
+	pq := aoc.PriorityQueue(func(a, b *queue) bool { return false })
+	pq.Insert(&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.Dequeue()
+		current := pq.ExtractMin()
 		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.Enqueue(next)
+				pq.Insert(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

day23/example.txt

@@ -0,0 +1,23 @@
+#.#####################
+#.......#########...###
+#######.#########.#.###
+###.....#.>.>.###.#.###
+###v#####.#v#.###.#.###
+###.>...#.#.#.....#...#
+###v###.#.#.#########.#
+###...#.#.#.......#...#
+#####.#.#.#######.#.###
+#.....#.#.#.......#...#
+#.#####.#.#.#########v#
+#.#...#...#...###...>.#
+#.#.#v#######v###.###v#
+#...#.>.#...>.>.#.###.#
+#####v#.#.###v#.#.###.#
+#.....#...#...#.#.#...#
+#.#########.###.#.#.###
+#...###...#...#...#.###
+###.###.#.###v#####v###
+#...#...#.#.>.>.#.>.###
+#.###.###.#.###.#.#v###
+#.....###...###...#...#
+#####################.#

day23/input.txt

@@ -0,0 +1,141 @@
+#.###########################################################################################################################################
+#.#...#.......#...#.....#...#...#######...###...#...#.......#...#...#...#...#...#...#...###...###...###...............#.....#...#######...###
+#.#.#.#.#####.#.#.#.###.#.#.#.#.#######.#.###.#.#.#.#.#####.#.#.#.#.#.#.#.#.#.#.#.#.#.#.###.#.###.#.###.#############.#.###.#.#.#######.#.###
+#.#.#.#.#.....#.#.#...#.#.#...#...#.....#...#.#.#.#.#.....#...#.#.#.#.#.#.#.#.#...#...#.....#.#...#...#.............#.#...#...#.......#.#...#
+#.#.#.#.#.#####.#.###.#.#.#######.#.#######.#.#.#.#.#####.#####.#.#.#.#.#.#.#.###############.#.#####.#############.#.###.###########.#.###.#
+#...#...#.....#.#.###.#.#.#.......#.....#...#.#.#.#.#.>.>.#.....#.#.#.#.#.#.#...#.............#.#.....#...#.......#.#.....#...........#.#...#
+#############.#.#v###.#.#.#.###########.#.###.#.#.#.#.#v###.#####.#.#.#.#.#.###.#.#############.#.#####.#.#.#####.#.#######.###########.#.###
+#...###...###...#.>.#.#.#.#.#...###.....#.....#.#.#...#...#.#...#.#.#.#.#.#.###.#.#####...###...#...#...#.#...#...#.....#...#...###...#.#.###
+#.#.###.#.#######v#.#.#.#.#.#.#.###.###########.#.#######.#.#.#.#.#.#.#.#.#.###.#.#####.#.###.#####.#.###.###.#.#######.#.###.#.###.#.#.#.###
+#.#.#...#.#.....#.#.#.#.#.#...#...#.........#...#.###.....#.#.#.#.#.#.#.#.#.>.>.#.......#.#...#.....#...#.#...#.#.......#...#.#.....#.#.#.###
+#.#.#.###.#.###.#.#.#.#.#.#######.#########.#.###.###.#####.#.#.#.#.#.#.#.###v###########.#.###.#######.#.#.###.#.#########.#.#######.#.#.###
+#.#.#...#.#...#.#.#.#.#.#...#.....#...#...#.#...#...#.....#.#.#.#.#.#.#...###.#...........#...#.....#...#.#...#.#.........#.#.#.......#.#.###
+#.#.###.#.###.#.#.#.#.#.###.#.#####.#.#.#.#.###.###.#####.#.#.#.#.#.#.#######.#.#############.#####.#.###.###.#.#########.#.#.#.#######.#.###
+#.#.....#.#...#.#.#.#.#.#...#.....#.#...#.#...#.#...#.....#...#...#.#.#.......#.#.....#.....#.#.....#...#.###.#.#...#.....#...#.#...###.#.###
+#.#######.#.###.#.#.#.#.#.#######.#.#####.###.#.#.###.#############.#.#.#######.#.###.#.###.#.#.#######.#.###.#.#.#.#.#########.#.#.###.#.###
+#.#...###...###.#.#...#.#...#.....#.#...#...#.#.#...#...........###...#.......#.#.#...#...#.#.#.#...###.#.###.#.#.#.#.....#.....#.#.#...#...#
+#.#.#.#########.#.#####.###.#.#####.#.#.###.#.#.###.###########.#############.#.#.#.#####.#.#.#.#.#.###.#.###.#.#.#.#####.#.#####.#.#.#####.#
+#.#.#.........#...#.....#...#.#...#...#...#...#.....#####.......#...###.......#.#.#.#.....#.#.#.#.#.#...#.>.>.#.#.#.#.....#...#...#...###...#
+#.#.#########.#####.#####.###.#.#.#######.###############.#######.#.###.#######.#.#.#.#####.#.#.#.#.#.#####v###.#.#.#.#######.#.#########.###
+#...#.......#.#...#...#...###.#.#.>.>...#...#...#...###...###...#.#...#.......#.#.#...###...#.#.#.#.#...#...###...#...###.....#.###.......###
+#####.#####.#.#.#.###.#.#####.#.###v###.###.#.#.#.#.###.#####.#.#.###.#######.#.#.#######.###.#.#.#.###.#.###############.#####.###.#########
+#...#.....#...#.#.###...#####...#...###.....#.#.#.#.#...#...#.#...#...#.......#.#.#.....#.....#.#.#.....#...#...........#.#...#...#...#.....#
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+###########################################################################################################################################.#

day23/main.go

@@ -0,0 +1,236 @@
+package main
+
+import (
+	"bufio"
+	_ "embed"
+	"fmt"
+	"strings"
+
+	aoc "go.sour.is/advent-of-code"
+)
+
+var log = aoc.Log
+
+func main() { aoc.MustResult(aoc.Runner(run)) }
+
+type result struct {
+	valuePT1 int
+	valuePT2 int
+}
+
+func (r result) String() string { return fmt.Sprintf("%#v", r) }
+
+func run(scan *bufio.Scanner) (*result, error) {
+	var m aoc.Map[int16, rune]
+
+	start := Point{0, 0}
+	target := Point{0, 0}
+	var text string
+	for scan.Scan() {
+		text = scan.Text()
+		if start == target {
+			start[1] = int16(strings.IndexRune(text, '.'))
+		}
+		m = append(m, []rune(text))
+	}
+	target[0] = int16(len(m) - 1)
+	target[1] = int16(strings.IndexRune(text, '.'))
+
+	result := &result{}
+
+	result.valuePT1 = search(&graph{m: m, start: start, target: target, neighbors: part1nbs})
+	result.valuePT2 = search(&graph{m: m, start: start, target: target, neighbors: part2nbs})
+
+	return result, nil
+}
+
+type Point = aoc.Point[int16]
+type Map = aoc.Map[int16, rune]
+
+// diretion of path steps
+type direction int8
+
+var (
+	U = Point{-1, 0}
+	R = Point{0, 1}
+	D = Point{1, 0}
+	L = Point{0, -1}
+)
+
+var directions = []Point{U, R, D, L}
+
+var dirIDX = func() map[Point]direction {
+	m := make(map[Point]direction, len(directions))
+	for k, v := range directions {
+		m[v] = direction(k)
+	}
+	return m
+}()
+
+var arrows = []rune{'^', '>', 'v', '<'}
+
+var arrowIDX = func() map[rune]Point {
+	m := make(map[rune]Point, len(arrows))
+	for k, v := range arrows {
+		m[v] = directions[k]
+	}
+	return m
+}()
+
+// position on the map
+type position struct {
+	loc       Point
+	direction Point
+}
+
+func (p position) step(to Point) position {
+	return position{p.loc.Add(to), to}
+}
+
+// implements FindPath graph interface
+type graph struct {
+	m      Map
+	start  Point
+	target Point
+
+	neighbors func(g *graph, current position) []position
+}
+
+// Neighbors returns valid steps from given position. if at target returns none.
+func (g *graph) Neighbors(current position) []position {
+	return g.neighbors(g, current)
+}
+
+// Cost calculates heat cost to neighbor from map
+func (g *graph) Cost(a, b position) int16 {
+	return 1
+}
+
+func (g *graph) Target(a position, c int16) bool {
+	return a.loc == g.target
+}
+
+func (g *graph) Seen(a position) position {
+	a.direction = Point{}
+	return a
+}
+
+func match[T comparable](match T, lis ...T) bool {
+	for _, b := range lis {
+		if b == match {
+			return true
+		}
+	}
+
+	return false
+}
+
+func search(g *graph) int {
+	costs, paths := aoc.FindPaths[int16, position](g, position{loc: g.start}, position{loc: g.target})
+
+	for i, path := range paths {
+		log("path length = ", costs[i])
+		printGraph(g.m, path)
+	}
+
+	return int(aoc.Max(0, costs...))
+}
+
+// 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
+	}
+
+	for r, row := range m {
+		for c, x := range row {
+			if _, ok := pts[Point{int16(r), int16(c)}]; ok {
+				if x == '.' {
+					fmt.Print("*")
+				} else {
+					fmt.Print(string(x))
+				}
+				continue
+			}
+			fmt.Print(".")
+			_ = x
+			// fmt.Print(string(x))
+		}
+		fmt.Println("")
+	}
+	fmt.Println("")
+}
+
+func opposite(d Point) Point {
+	return directions[(dirIDX[d]+2)%4]
+}
+
+
+func part1nbs(g *graph, current position) []position {
+	var nbs []position
+
+	if current.loc == g.start {
+		return []position{
+			{current.loc.Add(D), D},
+		}
+	}
+
+	if current.loc == g.target {
+		return nil
+	}
+
+	// only one direction on arrow.
+	_, r, _ := g.m.Get(current.loc)
+	if match(r, arrows...) {
+		to := arrowIDX[r]
+		if next := current.step(to); g.m.Valid(next.loc) {
+			_, r, _ := g.m.Get(next.loc)
+			d := arrows[(dirIDX[to]+2)%4] // flow from opposite direction
+			if !match(r, rune(d), '#') {
+				nbs = append(nbs, next)
+			}
+		}
+		return nbs
+	}
+
+	for _, to := range directions {
+		if next := current.step(to); g.m.Valid(next.loc) {
+			_, r, _ := g.m.Get(next.loc)
+			d := arrows[(dirIDX[to]+2)%4] // flow from opposite direction
+			if !match(r, rune(d), '#') {
+				nbs = append(nbs, next)
+			}
+		}
+	}
+	return nbs
+}
+
+func part2nbs(g *graph, current position) []position {
+	var nbs []position
+
+	if current.loc == g.start {
+		return []position{
+			{current.loc.Add(D), D},
+		}
+	}
+
+	if current.loc == g.target {
+		return nil
+	}
+
+	for _, to := range directions {
+		if next := current.step(to); g.m.Valid(next.loc) {
+			if next.direction == opposite(current.direction) {
+				continue
+			}
+			_, r, _ := g.m.Get(next.loc)
+			if r == '#' {
+				continue
+			}
+
+			nbs = append(nbs, next)
+		}
+	}
+	return nbs
+}

day23/main_test.go

@@ -0,0 +1,42 @@
+package main
+
+import (
+	"bufio"
+	"bytes"
+	"testing"
+
+	_ "embed"
+
+	"github.com/matryer/is"
+)
+
+//go:embed example.txt
+var example []byte
+
+//go:embed input.txt
+var input []byte
+
+func TestExample(t *testing.T) {
+	is := is.New(t)
+	scan := bufio.NewScanner(bytes.NewReader(example))
+
+	result, err := run(scan)
+	is.NoErr(err)
+
+	t.Log(result)
+	// is.Equal(result.valuePT1, 94)
+	is.Equal(result.valuePT2, 154)
+}
+
+// func TestSolution(t *testing.T) {
+// 	is := is.New(t)
+// 	scan := bufio.NewScanner(bytes.NewReader(input))
+
+// 	result, err := run(scan)
+// 	is.NoErr(err)
+
+// 	t.Log(result)
+// 	is.True(result.valuePT1 > 1918)
+// 	is.Equal(result.valuePT1, 2074)
+// 	is.Equal(result.valuePT2, 0)
+// }

grids.go

@@ -1,5 +1,14 @@
 package aoc
 
+import (
+	"cmp"
+	"fmt"
+	"sort"
+	"strings"
+
+	"golang.org/x/exp/maps"
+)
+
 type Vector struct {
 	Offset Point[int]
 	Scale  int
@@ -58,7 +67,7 @@ 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
@@ -66,13 +75,173 @@ 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 cmap[C number, N comparable] struct {
+	base      pather[C, N]
+	neighbors map[N]map[N]C
+}
+
+func (m *cmap[C, N]) Cost(a, b N) C {
+	if v, ok := m.neighbors[a]; ok {
+		return v[b]
+	}
+	return 0
+}
+func (m *cmap[C, N]) Neighbors(n N) []N {
+	if v, ok := m.neighbors[n]; ok {
+		return maps.Keys(v)
+	}
+	return nil
+}
+func (m *cmap[C, N]) Target(n N, c C) bool {
+	return m.base.Target(n, c)
+}
+func (m *cmap[C, N]) String() string {
+	var b = &strings.Builder{}
+
+	for k, nbs := range m.neighbors {
+		fmt.Fprintln(b, k)
+		for to, v := range nbs {
+			fmt.Fprintln(b, "  ", to, v)
+		}
+	}
+
+	return b.String()
+}
+
+func CompressMap[C number, N comparable](p pather[C, N], start N) pather[C, N] {
+	var next = []N{start}
+	var visited = make(map[N]map[N]C)
+
+	var n N
+	for len(next) > 0 {
+		n, next = next[len(next)-1], next[:len(next)-1]
+
+		if _, ok := visited[n]; ok {
+			continue
+		}
+
+		nbs := p.Neighbors(n)
+		if len(nbs) == 2{
+			a, b := nbs[0], nbs[1]
+			if to, ok := visited[a]; ok {
+				to[b] = to[n] + p.Cost(n, b)
+				delete(to, n)
+				visited[a] = to
+				continue
+			} else if to, ok := visited[b]; ok {
+				to[a] = to[n] + p.Cost(n, a)
+				delete(to, n)
+				visited[b] = to
+				continue
+			}
+		}
+
+		visited[n] = make(map[N]C)
+		next = append(next, nbs...)
+		for _, to := range nbs {
+			visited[n][to] = p.Cost(n, to)
+		}
+	}
+
+	return &cmap[C, N]{base: p, neighbors: visited}
+}
+
+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
+			}
+		}
+	}
+}

itertools_test.go

@@ -0,0 +1,44 @@
+package aoc_test
+
+import (
+	"testing"
+
+	"github.com/matryer/is"
+	aoc "go.sour.is/advent-of-code"
+)
+
+func TestReverse(t *testing.T) {
+	is := is.New(t)
+
+	is.Equal(aoc.Reverse([]int{1, 2, 3, 4}), []int{4, 3, 2, 1})
+}
+
+func TestReadStringToInts(t *testing.T) {
+	is := is.New(t)
+
+	is.Equal(aoc.ReadStringToInts([]string{"1", "2", "3"}), []int{1, 2, 3})
+}
+
+func TestRepeat(t *testing.T) {
+	is := is.New(t)
+
+	is.Equal(aoc.Repeat(5, 3), []int{5, 5, 5})
+}
+
+func TestTranspose(t *testing.T) {
+	is := is.New(t)
+
+	is.Equal(
+		aoc.Transpose(
+			[][]int{
+				{1, 1},
+				{0, 0},
+				{1, 1},
+			},
+		),
+		[][]int{
+			{1, 0, 1},
+			{1, 0, 1},
+		},
+	)
+}

math_test.go

@@ -0,0 +1,33 @@
+package aoc_test
+
+import (
+	"testing"
+
+	"github.com/matryer/is"
+	aoc "go.sour.is/advent-of-code"
+)
+
+func TestLCM(t *testing.T) {
+	is := is.New(t)
+
+	is.Equal(aoc.LCM([]int{}...), 0)
+	is.Equal(aoc.LCM(5), 5)
+	is.Equal(aoc.LCM(5, 3), 15)
+	is.Equal(aoc.LCM(5, 3, 2), 30)
+}
+
+func TestPower2(t *testing.T) {
+	is := is.New(t)
+
+	is.Equal(aoc.Power2(0), 1)
+	is.Equal(aoc.Power2(1), 2)
+	is.Equal(aoc.Power2(2), 4)
+}
+
+func TestABS(t *testing.T) {
+	is := is.New(t)
+
+	is.Equal(aoc.ABS(1), 1)
+	is.Equal(aoc.ABS(0), 0)
+	is.Equal(aoc.ABS(-1), 1)
+}

runner.go

@@ -2,26 +2,70 @@ 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)
 	}
 
-	input, err := os.Open(os.Args[1])
+	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)
 	if err != nil {
 		Log(err)
 		os.Exit(1)
 	}
 
 	scan := bufio.NewScanner(input)
+
 	return run(scan)
 }
 

search.go

@@ -1,12 +1,14 @@
 package aoc
 
 import (
+	"maps"
+	"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
@@ -16,10 +18,10 @@ 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]) Enqueue(elem T) {
+func (pq *priorityQueue[T]) Insert(elem *T) {
 	pq.totalEnqueue++
 
 	pq.elems = append(pq.elems, elem)
@@ -28,35 +30,41 @@ func (pq *priorityQueue[T]) Enqueue(elem T) {
 func (pq *priorityQueue[T]) IsEmpty() bool {
 	return len(pq.elems) == 0
 }
-func (pq *priorityQueue[T]) Dequeue() (T, bool) {
+func (pq *priorityQueue[T]) ExtractMin() *T {
 	pq.totalDequeue++
 
-	var elem T
+	var elem *T
 	if pq.IsEmpty() {
-		return elem, false
+		return elem
 	}
 
-	sort.Slice(pq.elems, func(i, j int) bool { return pq.less(pq.elems[i], pq.elems[j]) })
+	sort.Slice(pq.elems, func(i, j int) bool { return pq.less(pq.elems[j], pq.elems[i]) })
 	pq.elems, elem = pq.elems[:len(pq.elems)-1], pq.elems[len(pq.elems)-1]
-	return elem, true
+	return elem
 }
 
 // ManhattanDistance the distance between two points measured along axes at right angles.
 func ManhattanDistance[T integer](a, b Point[T]) T {
-	return ABS(a[1]-b[1]) + ABS(a[0]-b[0])
+	return ABS(a[0]-b[0]) + ABS(a[1]-b[1])
 }
 
 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
-	Potential(a, b N) C
+
+	// Target returns true when target reached. receives node and cost.
+	Target(N, C) bool
 
 	// 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.
@@ -67,9 +75,18 @@ 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) {
+func FindPath[C integer, N comparable](g pather[C, N], start, end N) (C, []N, map[N]C) {
 	var zero C
-	closed := make(map[N]bool)
+
+	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
+	}
 
 	type node struct {
 		cost      C
@@ -78,6 +95,260 @@ func FindPath[C integer, N comparable](g pather[C, N], start, end N) (C, []N) {
 		position  N
 	}
 
+	newPath := func(n *node) []N {
+		var path []N
+		for n.parent != nil {
+			path = append(path, n.position)
+			n = n.parent
+		}
+		path = append(path, n.position)
+
+		Reverse(path)
+		return path
+	}
+
+	less := func(a, b *node) bool {
+		return a.cost+a.potential < b.cost+b.potential
+	}
+
+	closed := make(map[N]C)
+	open := FibHeap(less)
+
+	open.Insert(&node{position: start, potential: potentialFn(start)})
+	closed[start] = zero
+
+	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),
+			}
+
+			seen := seenFn(nb)
+			cost, ok := closed[seen]
+			if !ok || next.cost < cost {
+				open.Insert(next)
+				closed[seen] = next.cost
+			}
+
+			if next.potential == zero && g.Target(next.position, next.cost) {
+				return next.cost, newPath(next), closed
+			}
+		}
+	}
+	return zero, nil, closed
+}
+
+type fibTree[T any] struct {
+	value  *T
+	parent *fibTree[T]
+	child  []*fibTree[T]
+	mark   bool
+}
+
+func (t *fibTree[T]) Value() *T { return t.value }
+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)+1)
+	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
+	if h.least == nil || a.least != nil && h.less(a.least.value, h.least.value) {
+		h.least = a.least
+	}
+}
+
+func (h *fibHeap[T]) find(fn func(*T) bool) *fibTree[T] {
+	var st []*fibTree[T]
+	st = append(st, h.trees...)
+	var tr *fibTree[T]
+
+	for len(st) > 0 {
+		tr, st = st[0], st[1:]
+		ro := *tr.value
+		if fn(&ro) {
+			break
+		}
+		st = append(st, tr.child...)
+	}
+
+	return tr
+}
+
+func (h *fibHeap[T]) Find(fn func(*T) bool) *T {
+	if needle := h.find(fn); needle != nil {
+		return needle.value
+	}
+
+	return nil
+}
+
+func (h *fibHeap[T]) DecreaseKey(find func(*T) bool, decrease func(*T)) {
+	needle := h.find(find)
+	if needle == nil {
+		return
+	}
+	decrease(needle.value)
+
+	if h.less(needle.value, h.least.value) {
+		h.least = needle
+	}
+
+	if parent := needle.parent; parent != nil {
+		if h.less(needle.value, parent.value) {
+			h.cut(needle)
+			h.cascadingCut(parent)
+		}
+	}
+}
+
+func (h *fibHeap[T]) cut(x *fibTree[T]) {
+	parent := x.parent
+	for i := range parent.child {
+		pos := parent.child[i]
+		if pos == x {
+			parent.child[i] = parent.child[len(parent.child)-1]
+			parent.child = parent.child[:len(parent.child)-1]
+			break
+		}
+	}
+
+	x.parent = nil
+	x.mark = false
+	h.trees = append(h.trees, x)
+
+	if h.less(x.value, h.least.value) {
+		h.least = x
+	}
+}
+
+func (h *fibHeap[T]) cascadingCut(y *fibTree[T]) {
+	if y.parent != nil {
+		if !y.mark {
+			y.mark = true
+			return
+		}
+
+		h.cut(y)
+		h.cascadingCut(y.parent)
+	}
+}
+
+// FindPath uses the A* path finding algorithem.
+// g is the graph source that implements the pather interface.
+//
+//	C is an numeric type for calculating cost/potential
+//	N is the node values. is comparable for storing in visited table for pruning.
+//
+// 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 FindPaths[C integer, N comparable](g pather[C, N], start, end N) ([]C, [][]N) {
+	var zero C
+	// closed := make(map[N]bool)
+
+	var potentialFn = func(N) C { var zero C; return zero }
+	if p, ok := g.(interface{ Potential(N) C }); ok {
+		potentialFn = p.Potential
+	}
+
+	type node struct {
+		cost      C
+		potential C
+		parent    *node
+		position  N
+		closed    map[N]bool
+	}
+
 	NewPath := func(n *node) []N {
 		var path []N
 		for n.parent != nil {
@@ -90,13 +361,12 @@ func FindPath[C integer, N comparable](g pather[C, N], start, end N) (C, []N) {
 		return path
 	}
 
-	less := func(a, b node) bool {
+	less := func(b, a *node) bool {
 		return b.cost+b.potential < a.cost+a.potential
 	}
 
 	pq := PriorityQueue(less)
-	pq.Enqueue(node{position: start})
-	closed[start] = false
+	pq.Insert(&node{position: start, closed: make(map[N]bool)})
 
 	defer func() {
 		Log("queue max depth = ", pq.maxDepth, "total enqueue = ", pq.totalEnqueue, "total dequeue = ", pq.totalDequeue)
@@ -107,44 +377,51 @@ func FindPath[C integer, N comparable](g pather[C, N], start, end N) (C, []N) {
 		seenFn = s.Seen
 	}
 
-	var targetFn = func(a N) bool { return true }
-	if s, ok := g.(interface{ Target(N) bool }); ok {
+	var targetFn = func(n N, c C) bool { return true }
+	if s, ok := g.(interface{ Target(N, C) bool }); ok {
 		targetFn = s.Target
 	}
 
+	var paths [][]N
+	var costs []C
+
 	for !pq.IsEmpty() {
-		current, _ := pq.Dequeue()
+		current := pq.ExtractMin()
 		cost, potential, n := current.cost, current.potential, current.position
 
 		seen := seenFn(n)
-		if closed[seen] {
+		if current.closed[seen] {
 			continue
 		}
-		closed[seen] = true
+		current.closed[seen] = true
 
-		if cost > 0 && potential == zero && targetFn(current.position) {
-			return cost, NewPath(&current)
+		if cost > 0 && potential == zero && cost > Max(0, costs...) && targetFn(current.position, cost) {
+			paths = append([][]N(nil), NewPath(current))
+			costs = append([]C(nil), cost)
+			Log("new record = ", cost)
+			continue
 		}
 
 		for _, nb := range g.Neighbors(n) {
 			seen := seenFn(nb)
-			if closed[seen] {
+			if current.closed[seen] {
 				continue
 			}
 
 			cost := g.Cost(n, nb) + current.cost
-			nextPath := node{
+			next := &node{
 				position:  nb,
-				parent:    &current,
+				parent:    current,
 				cost:      cost,
-				potential: g.Potential(nb, end),
+				potential: potentialFn(nb),
+				closed:    maps.Clone(current.closed),
 			}
 			// check if path is in open list
-			if _, open := closed[seen]; !open {
-				pq.Enqueue(nextPath)
-				closed[seen] = false // add to open list
+			if _, open := current.closed[seen]; !open {
+				next.closed[seen] = false // add to open list
+				pq.Insert(next)
 			}
 		}
 	}
-	return zero, nil
+	return costs, paths
 }

set_test.go

@@ -0,0 +1,27 @@
+package aoc_test
+
+import (
+	"sort"
+	"testing"
+
+	"github.com/matryer/is"
+	aoc "go.sour.is/advent-of-code"
+)
+
+func TestSet(t *testing.T) {
+	is := is.New(t)
+
+	s := aoc.Set(1, 2, 3)
+	is.True(!s.Has(0))
+	is.True(s.Has(1))
+	is.True(s.Has(2))
+	is.True(s.Has(3))
+	is.True(!s.Has(4))
+
+	s.Add(4)
+	is.True(s.Has(4))
+
+	items := s.Items()
+	sort.Ints(items)
+	is.Equal(items, []int{1, 2, 3, 4})
+}