day25: wow, part 1

with cycles removal not working

.gitignore

@@ -1,3 +1,4 @@
 /.direnv/
 /.go
 input
+*.png

day25/Snowerload.go

@@ -0,0 +1,10 @@
+package day25
+
+import (
+	"fmt"
+)
+
+func Run() int {
+	fmt.Println("time to wrap things up")
+	return 0
+}

day25/example

@@ -0,0 +1,13 @@
+jqt: rhn xhk nvd
+rsh: frs pzl lsr
+xhk: hfx
+cmg: qnr nvd lhk bvb
+rhn: xhk bvb hfx
+bvb: xhk hfx
+pzl: lsr hfx nvd
+qnr: nvd
+ntq: jqt hfx bvb xhk
+nvd: lhk
+lsr: lhk
+rzs: qnr cmg lsr rsh
+frs: qnr lhk lsr

day25/example-after-removing.mmd

@@ -0,0 +1,15 @@
+flowchart TD
+	cmg --- qnr
+	cmg --- lhk
+	jqt --- nvd
+	bvb --- rhn
+	lsr --- pzl
+	lhk --- lsr
+	lsr --- rsh
+	hfx --- ntq
+	qnr --- rzs
+	bvb --- hfx
+	lhk --- nvd
+	frs --- qnr
+	jqt --- ntq
+	rhn --- xhk

day25/example-before-removing.mmd

@@ -0,0 +1,34 @@
+flowchart TD
+	ntq --- xhk
+	bvb --- hfx
+	lsr --- pzl
+	nvd --- pzl
+	pzl --- rsh
+	frs --- lhk
+	bvb --- cmg
+	jqt --- xhk
+	bvb --- rhn
+	jqt --- rhn
+	hfx --- xhk
+	frs --- lsr
+	lhk --- lsr
+	jqt --- nvd
+	cmg --- rzs
+	hfx --- pzl
+	bvb --- xhk
+	rhn --- xhk
+	frs --- rsh
+	cmg --- qnr
+	nvd --- qnr
+	qnr --- rzs
+	bvb --- ntq
+	frs --- qnr
+	cmg --- nvd
+	hfx --- rhn
+	jqt --- ntq
+	hfx --- ntq
+	lsr --- rsh
+	cmg --- lhk
+	rsh --- rzs
+	lhk --- nvd
+	lsr --- rzs

day25/example-graph.mmd

@@ -0,0 +1,34 @@
+flowchart TD
+	hfx --- pzl
+	cmg --- lhk
+	lsr --- rsh
+	rsh --- rzs
+	bvb --- rhn
+	jqt --- xhk
+	nvd --- pzl
+	lsr --- pzl
+	frs --- qnr
+	frs --- lsr
+	lhk --- lsr
+	lsr --- rzs
+	rhn --- xhk
+	hfx --- ntq
+	nvd --- qnr
+	qnr --- rzs
+	bvb --- xhk
+	hfx --- xhk
+	jqt --- rhn
+	jqt --- nvd
+	cmg --- nvd
+	lhk --- nvd
+	frs --- rsh
+	ntq --- xhk
+	cmg --- rzs
+	bvb --- ntq
+	cmg --- qnr
+	hfx --- rhn
+	jqt --- ntq
+	bvb --- cmg
+	frs --- lhk
+	pzl --- rsh
+	bvb --- hfx

day25/example2

@@ -0,0 +1,3 @@
+jqt: rhn nvd rsh
+rsh: frs pzl lsr
+xhk: hfx

day25/graph.go

@@ -0,0 +1,301 @@
+package day25
+
+import (
+	"fmt"
+	"log"
+	"os"
+	"strings"
+
+	mapset "github.com/deckarep/golang-set/v2"
+)
+
+type Graph struct {
+	Nodes map[string]*Node
+}
+
+type Node struct {
+	Name      string
+	Neighbors mapset.Set[string]
+}
+
+func (n Node) String() string {
+	return fmt.Sprintf("[%s : %+v]", n.Name, n.Neighbors)
+}
+
+func ReadGraphFile(filename string) (g Graph) {
+	g.Nodes = map[string]*Node{}
+
+	bytes, err := os.ReadFile(filename)
+	if err != nil {
+		panic(err)
+	}
+	text := strings.TrimSpace(string(bytes))
+	for _, line := range strings.Split(text, "\n") {
+		g.readGraphLine(line)
+	}
+
+	return
+}
+
+func (g *Graph) readGraphLine(l string)  {
+	firstSplit := strings.Split(l, ":")
+
+	node, exists := g.Nodes[firstSplit[0]]
+	if !exists {
+		node = &Node{
+			Name:      firstSplit[0],
+			Neighbors: mapset.NewSet[string](),
+		}
+	}
+
+	secondSplit := strings.Fields(firstSplit[1])
+
+	for _, neighborName := range secondSplit {
+		neighbor, exists := g.Nodes[neighborName]
+		if !exists {
+			neighbor = &Node{
+				Name:      neighborName,
+				Neighbors: mapset.NewSet[string](),
+			}
+			g.Nodes[neighborName] = neighbor
+		}
+		neighbor.Neighbors.Add(node.Name)
+		node.Neighbors.Add(neighbor.Name)
+	}
+
+	g.Nodes[node.Name] = node
+
+	return
+}
+
+// NOTE this is so sad. nodeA.Neighbors.Remove(nodeB.Name) hangs for a reason i don't understand
+func (g *Graph) RemoveEdge(a, b string) {
+	// log.Printf("entering remove edge for %s and %s", a, b)
+	nodeA, existsA := g.Nodes[a]
+	// log.Println("got first node", nodeA, existsA)
+	nodeB, existsB := g.Nodes[b]
+	// log.Println("got second node", nodeB, existsB)
+	if !existsA || !existsB {
+		panic("requesting not found node")
+	}
+
+	// log.Println("before removals")
+	// log.Println("before remove first", nodeA)
+	// nodeA.Neighbors = newANeighbors
+	nodeA.Neighbors = nodeA.Neighbors.Difference(mapset.NewSet[string](nodeB.Name))
+	// nodeA.Neighbors.Remove(nodeB.Name)
+	// log.Println("removed first", nodeA)
+
+	// log.Println("before remove second", nodeB)
+	// nodeB.Neighbors = newBNeighbors
+	nodeB.Neighbors = nodeB.Neighbors.Difference(mapset.NewSet[string](nodeA.Name))
+	// nodeB.Neighbors.Remove(nodeA.Name)
+	// log.Println("removed second", nodeB)
+}
+
+func (g *Graph) AddEdge(a, b string) {
+	nodeA, existsA := g.Nodes[a]
+	nodeB, existsB := g.Nodes[b]
+	if !existsA || !existsB {
+		panic("requesting not found node")
+	}
+	nodeA.Neighbors.Add(nodeB.Name)
+	nodeB.Neighbors.Add(nodeA.Name)
+}
+
+func (g *Graph) findCycle() (from, to string, exists bool) {
+	// log.Printf(">>>> starting new find cycle")
+	var firstNode *Node
+	for _, n := range g.Nodes {
+		firstNode = n
+		break
+	}
+	// log.Printf("initial search from %s and neighbors %+v", firstNode.Name, firstNode.Neighbors)
+	for neighborName := range firstNode.Neighbors.Iter() {
+		initialVisited := mapset.NewSet[string](firstNode.Name)
+		// log.Printf("initial dfs from %s to %s with initial visited %+v", firstNode.Name, neighborName, initialVisited)
+		from, to, exists = g.dfcCycle(firstNode.Name, neighborName, initialVisited)
+		if exists {
+			break
+		}
+	}
+
+	// log.Printf("<<<< cycle %t, from %s to %s", exists, from, to)
+	return
+}
+
+func (g *Graph) dfcCycle(fromName, atName string, visited mapset.Set[string]) (cycleFrom, cycleTo string, cycleExists bool) {
+	// log.Printf("> step from %+v to %+v. visited : %+v", fromName, atName, visited)
+	if visited.Cardinality() == len(g.Nodes) {
+		log.Println("exit by visited all")
+		return
+	}
+
+	atNode := g.Nodes[atName]
+
+	if visited.Contains(atName) {
+		return fromName, atName, true
+	}
+
+	for neighborName := range atNode.Neighbors.Iter() {
+		if neighborName == fromName {
+			continue
+		}
+		newVisited := visited.Clone()
+		newVisited.Add(atName)
+		cycleFrom, cycleTo, cycleExists = g.dfcCycle(atName, neighborName, newVisited)
+		if cycleExists {
+			break
+		}
+	}
+
+	return
+}
+
+func (g *Graph) ComponentFrom(fromName string) (component mapset.Set[string]) {
+	startNode := g.Nodes[fromName]
+	component = mapset.NewSet[string](startNode.Name)
+	toVisit := startNode.Neighbors.Clone()
+
+	for toVisit.Cardinality() > 0 {
+		runnerNodeName, _ := toVisit.Pop()
+		if component.Contains(runnerNodeName) {
+			continue
+		}
+		component.Add(runnerNodeName)
+		runnerNode := g.Nodes[runnerNodeName]
+		unvisitedNeighbors := runnerNode.Neighbors.Difference(component)
+		// log.Printf("adding %s to component. neighbors %+v, adding %+v to visit",
+		// 	runnerNodeName, runnerNode.Neighbors, unvisitedNeighbors)
+		toVisit = toVisit.Union(unvisitedNeighbors)
+	}
+
+	return
+}
+
+func (g *Graph) ToMermaid() (result string) {
+	result += "flowchart TD\n"
+	edges := mapset.NewSet[string]()
+
+	for _, node := range g.Nodes {
+		for neighborName := range node.Neighbors.Iter() {
+			var first, second string
+			if node.Name < neighborName {
+				first = node.Name
+				second = neighborName
+			} else {
+				first = neighborName
+				second = node.Name
+			}
+			edges.Add(fmt.Sprintf("\t%s --- %s\n", first, second))
+		}
+	}
+
+	for line := range edges.Iter() {
+		result += line
+	}
+	return
+}
+
+func (g *Graph)SaveAsMermaid(filename string) {
+	mmd := g.ToMermaid()
+
+	file, err := os.Create(filename)
+	if err != nil {
+		panic(err)
+	}
+	defer func() {
+		if err := file.Close(); err != nil {
+			panic(err)
+		}
+	}()
+
+	file.WriteString(mmd)
+}
+
+type Edge struct {
+	smaller, bigger string
+}
+func (e Edge)String() string {
+	return fmt.Sprintf("%s/%s", e.smaller, e.bigger)
+}
+
+func CreateEdge(a, b string) Edge {
+	var smaller, bigger string
+	if a < b {
+		smaller = a
+		bigger = b
+	} else {
+		smaller = b
+		bigger = a
+	}
+	return Edge{smaller, bigger}
+}
+
+func (g *Graph) RemoveAllCycles() (removedEdges mapset.Set[Edge]) {
+	removedEdges = mapset.NewSet[Edge]()
+	hasCycle := true
+	var from, to string
+	for hasCycle {
+		from, to, hasCycle = g.findCycle()
+		if hasCycle {
+			// log.Printf("\n!!!! found cycle %s to %s\n", from, to)
+			edgeToRemove := CreateEdge(from, to)
+			removedEdges.Add(edgeToRemove)
+			g.RemoveEdge(from, to)
+		}
+	}
+	return
+}
+
+func (g *Graph) TryToSplit() (componentSizeMult int) {
+	// first remove all cycles
+	removedEdges := g.RemoveAllCycles()
+	g.SaveAsMermaid("after-removing-cycles.mmd")
+	// log.Printf("all removed edges %+v, two of them are necessary to split initial graph into 2 ", removedEdges)
+
+	triedEdges := mapset.NewSet[Edge]()
+
+	for _, node := range g.Nodes {
+		for neighborName := range node.Neighbors.Iter() {
+			edge := CreateEdge(neighborName, node.Name)
+			if triedEdges.Contains(edge) {
+				continue
+			}
+			triedEdges.Add(edge)
+			// first remove the edge
+			g.RemoveEdge(edge.bigger, edge.smaller)
+
+			// then ask for components of the nodes of removed edge
+			compA := g.ComponentFrom(edge.bigger)
+			compB := g.ComponentFrom(edge.smaller)
+
+			// iterate over the initially removed edges. only two of them should be 'connecting'
+			// i.e were necessary to remove
+			necessaryEdgesCount := 0
+			for initiallyRemovedEdge := range removedEdges.Iter() {
+				endA, endB := initiallyRemovedEdge.bigger, initiallyRemovedEdge.smaller
+				isNonNecessary := (compA.Contains(endA) && compA.Contains(endB)) || (compB.Contains(endA) && compB.Contains(endB))
+				if !isNonNecessary {
+					// log.Printf("with edge %+v test removed, the %+v also seems necessary", edge, initiallyRemovedEdge)
+					necessaryEdgesCount += 1
+				}
+			}
+			// log.Printf("with edge %+v test removed neessary count is %d", edge, necessaryEdgesCount)
+
+			// if we found 2 necessary, then our currently tried edge is the third necesary to remove
+			// and out two components are the searched
+			if necessaryEdgesCount == 2 {
+				return compA.Cardinality() * compB.Cardinality()
+			}
+
+			// in the end add edge back if not fitting
+			g.AddEdge(edge.bigger, edge.smaller)
+		}
+	}
+
+	// now huh. if we didn't find `necessaryEdgesCount == 2`
+	// that means 0, 1 or 3
+
+	return
+}

day25/graph_test.go

@@ -0,0 +1,96 @@
+package day25
+
+import (
+	"testing"
+
+	mapset "github.com/deckarep/golang-set/v2"
+)
+
+func TestReadFileExample(t *testing.T) {
+	filename := "example"
+	g := ReadGraphFile(filename)
+	t.Logf("read graph %+v", g)
+}
+
+func TestRemoveEdge(t *testing.T) {
+	filename := "example"
+	g := ReadGraphFile(filename)
+	t.Logf("read graph %+v", g)
+
+	g.RemoveEdge("bvb", "hfx")
+	t.Logf("after removing bvb-hfv %+v", g)
+}
+
+func TestCreateExampleMermaid(t *testing.T) {
+	filename := "example"
+	g := ReadGraphFile(filename)
+
+	g.SaveAsMermaid("example-graph.mmd")
+}
+
+func TestComponentOnInitial(t *testing.T) {
+	// should be all nodes
+	filename := "example"
+	g := ReadGraphFile(filename)
+	comp := g.ComponentFrom("bvb")
+	t.Logf("got component %+v", comp)
+	if comp.Cardinality() != len(g.Nodes) {
+		t.Errorf("should have same size!")
+	}
+}
+
+func TestComponentOnMini(t *testing.T) {
+	// should be all nodes
+	filename := "example2"
+	g := ReadGraphFile(filename)
+	comp := g.ComponentFrom("jqt")
+	t.Logf("got component %+v", comp)
+	if comp.Cardinality() == len(g.Nodes) {
+		t.Errorf("should have different size!")
+	}
+}
+
+func TestRemoveAllCycles(t *testing.T) {
+	filename := "example"
+	g := ReadGraphFile(filename)
+	g.SaveAsMermaid("example-before-removing.mmd")
+	t.Logf("initial graph is %+v", g)
+	edges := g.RemoveAllCycles()
+	expectedNecessary := mapset.NewSet[Edge](
+		CreateEdge("hfx", "pzl"),
+		CreateEdge("bvb", "cmg"),
+		CreateEdge("nvd", "jqt"),
+	)
+
+	intersection := expectedNecessary.Intersect(edges)
+	t.Logf("i expect that exactly two will be in intersection %+v", intersection)
+	if intersection.Cardinality() != 2 {
+		panic("huh?")
+		// ok, this is not what i expected.
+		// this is unstable. but i could run it several times? and hopefully luck out?
+	}
+
+	t.Logf("removed edges %+v", edges)
+	t.Logf("after removal graph is %+v", g)
+	g.SaveAsMermaid("example-after-removing.mmd")
+}
+
+func TestSplittingExample(t *testing.T) {
+	filename := "example"
+	g := ReadGraphFile(filename)
+	result := g.TryToSplit()
+	t.Logf("hopefully same as example answer: %d", result)
+}
+
+func TestSplittingInput(t *testing.T) {
+	// kind of brute force
+	result := 0
+	filename := "input"
+
+	for result == 0 {
+		g := ReadGraphFile(filename)
+		result = g.TryToSplit()
+		t.Logf("hopefully as answer: %d", result)
+	}
+
+}

day25/notes.org

@@ -0,0 +1,480 @@
+#+title: Notes
+* ok, not so simple
+'how to find 3 edges which if removed split graph into 2 components'
+
+i guess i could find all cycles?
+and then what?
+
+then if i have graph without cycles and all of the removed edges,
+maybe i can figure out how to remove one edge, to make two components, and all (k - 2) edges back in a way that would not connect those components.
+
+well, the cycles maybe should have been broken elsewhere?
+for most cycles - it doesn't matter.
+
+for cycles that break into 2 components, does it?
+
+ok. if i have the no-cycle graph.
+then we can maybe start searching for 'third' edge to remove.
+
+i remove it, i get two components.
+then as a test - exactly two edges when added should connect those components.
+if that happens - i have an answer
+
+sounds good
+** making code to get components.
+now.
+** make method to remove all cycles.
+save the removed edges to slice
+
+i guess could be a method that modifies the graph and returns all removed edges.
+and test that
+** why a node ends up without any edges?
+#+begin_src
+=== RUN   TestRemoveAllCycles
+    graph_test.go:55: initial graph is {Nodes:map[bvb:[bvb : Set{xhk, hfx, ntq}] cmg:[cmg : Set{qnr, nvd, lhk, bvb, rzs}] frs:[frs : Set{qnr, lhk, lsr}] hfx:[hfx : Set{rhn, bvb, pzl, ntq, xhk}] jqt:[jqt : Set{rhn, xhk, nvd, ntq}] lhk:[lhk : Set{nvd, lsr, frs, cmg}] lsr:[lsr : Set{rzs, frs, lhk}] ntq:[ntq : Set{jqt, hfx, bvb, xhk}] nvd:[nvd : Set{lhk}] pzl:[pzl : Set{lsr, hfx, nvd}] qnr:[qnr : Set{nvd, rzs, frs}] rhn:[rhn : Set{bvb, hfx, xhk}] rsh:[rsh : Set{lsr, rzs, frs, pzl}] rzs:[rzs : Set{lsr, rsh, qnr, cmg}] xhk:[xhk : Set{hfx, rhn, bvb, ntq}]]}
+2023/12/25 08:14:02 >>>> starting new find cycle
+2023/12/25 08:14:02 initial search from lsr and neighbors Set{lhk, rzs, frs}
+2023/12/25 08:14:02 initial dfs from lsr to lhk with initial visited Set{lsr}
+2023/12/25 08:14:02 > step from lsr to lhk. visited : Set{lsr}
+2023/12/25 08:14:02 > step from lhk to frs. visited : Set{lsr, lhk}
+2023/12/25 08:14:02 > step from frs to lsr. visited : Set{lhk, frs, lsr}
+2023/12/25 08:14:02 <<<< cycle true, from frs to lsr
+2023/12/25 08:14:02 entering remove edge for frs and lsr
+2023/12/25 08:14:02 removed first [frs : Set{qnr, lhk}]
+2023/12/25 08:14:02 removed second [lsr : Set{lhk, rzs}]
+2023/12/25 08:14:02 >>>> starting new find cycle
+2023/12/25 08:14:02 initial search from xhk and neighbors Set{hfx, rhn, bvb, ntq}
+2023/12/25 08:14:02 initial dfs from xhk to ntq with initial visited Set{xhk}
+2023/12/25 08:14:02 > step from xhk to ntq. visited : Set{xhk}
+2023/12/25 08:14:02 > step from ntq to jqt. visited : Set{xhk, ntq}
+2023/12/25 08:14:02 > step from jqt to rhn. visited : Set{xhk, ntq, jqt}
+2023/12/25 08:14:02 > step from rhn to bvb. visited : Set{rhn, xhk, ntq, jqt}
+2023/12/25 08:14:02 > step from bvb to xhk. visited : Set{xhk, ntq, jqt, rhn, bvb}
+2023/12/25 08:14:02 <<<< cycle true, from bvb to xhk
+2023/12/25 08:14:02 entering remove edge for bvb and xhk
+2023/12/25 08:14:02 removed first [bvb : Set{hfx, ntq}]
+2023/12/25 08:14:02 removed second [xhk : Set{ntq, hfx, rhn}]
+2023/12/25 08:14:02 >>>> starting new find cycle
+2023/12/25 08:14:02 initial search from rhn and neighbors Set{bvb, hfx, xhk}
+2023/12/25 08:14:02 initial dfs from rhn to xhk with initial visited Set{rhn}
+2023/12/25 08:14:02 > step from rhn to xhk. visited : Set{rhn}
+2023/12/25 08:14:02 > step from xhk to hfx. visited : Set{rhn, xhk}
+2023/12/25 08:14:02 > step from hfx to bvb. visited : Set{rhn, xhk, hfx}
+2023/12/25 08:14:02 > step from bvb to hfx. visited : Set{hfx, rhn, xhk, bvb}
+2023/12/25 08:14:02 <<<< cycle true, from bvb to hfx
+2023/12/25 08:14:02 entering remove edge for bvb and hfx
+2023/12/25 08:14:02 removed first [bvb : Set{ntq}]
+2023/12/25 08:14:02 removed second [hfx : Set{rhn, pzl, ntq, xhk}]
+2023/12/25 08:14:02 >>>> starting new find cycle
+2023/12/25 08:14:02 initial search from rsh and neighbors Set{frs, pzl, lsr, rzs}
+2023/12/25 08:14:02 initial dfs from rsh to frs with initial visited Set{rsh}
+2023/12/25 08:14:02 > step from rsh to frs. visited : Set{rsh}
+2023/12/25 08:14:02 > step from frs to qnr. visited : Set{rsh, frs}
+2023/12/25 08:14:02 > step from qnr to nvd. visited : Set{qnr, rsh, frs}
+2023/12/25 08:14:02 > step from nvd to lhk. visited : Set{rsh, frs, qnr, nvd}
+2023/12/25 08:14:02 > step from lhk to cmg. visited : Set{rsh, frs, qnr, nvd, lhk}
+2023/12/25 08:14:02 > step from cmg to qnr. visited : Set{rsh, frs, qnr, nvd, lhk, cmg}
+2023/12/25 08:14:02 <<<< cycle true, from cmg to qnr
+2023/12/25 08:14:02 entering remove edge for cmg and qnr
+2023/12/25 08:14:02 removed first [cmg : Set{nvd, lhk, bvb, rzs}]
+2023/12/25 08:14:02 removed second [qnr : Set{nvd, rzs, frs}]
+2023/12/25 08:14:02 >>>> starting new find cycle
+2023/12/25 08:14:02 initial search from rzs and neighbors Set{rsh, qnr, cmg, lsr}
+2023/12/25 08:14:02 initial dfs from rzs to cmg with initial visited Set{rzs}
+2023/12/25 08:14:02 > step from rzs to cmg. visited : Set{rzs}
+2023/12/25 08:14:02 > step from cmg to nvd. visited : Set{rzs, cmg}
+2023/12/25 08:14:02 > step from nvd to lhk. visited : Set{cmg, nvd, rzs}
+2023/12/25 08:14:02 > step from lhk to cmg. visited : Set{cmg, lhk, nvd, rzs}
+2023/12/25 08:14:02 <<<< cycle true, from lhk to cmg
+2023/12/25 08:14:02 entering remove edge for lhk and cmg
+2023/12/25 08:14:02 removed first [lhk : Set{frs, nvd, lsr}]
+2023/12/25 08:14:02 removed second [cmg : Set{rzs, nvd, bvb}]
+2023/12/25 08:14:02 >>>> starting new find cycle
+2023/12/25 08:14:02 initial search from qnr and neighbors Set{nvd, rzs, frs}
+2023/12/25 08:14:02 initial dfs from qnr to nvd with initial visited Set{qnr}
+2023/12/25 08:14:02 > step from qnr to nvd. visited : Set{qnr}
+2023/12/25 08:14:02 > step from nvd to lhk. visited : Set{qnr, nvd}
+2023/12/25 08:14:02 > step from lhk to nvd. visited : Set{lhk, qnr, nvd}
+2023/12/25 08:14:02 <<<< cycle true, from lhk to nvd
+2023/12/25 08:14:02 entering remove edge for lhk and nvd
+2023/12/25 08:14:02 removed first [lhk : Set{lsr, frs}]
+2023/12/25 08:14:02 removed second [nvd : Set{}]
+2023/12/25 08:14:02 >>>> starting new find cycle
+2023/12/25 08:14:02 initial search from jqt and neighbors Set{rhn, xhk, nvd, ntq}
+2023/12/25 08:14:02 initial dfs from jqt to xhk with initial visited Set{jqt}
+2023/12/25 08:14:02 > step from jqt to xhk. visited : Set{jqt}
+2023/12/25 08:14:02 > step from xhk to ntq. visited : Set{jqt, xhk}
+2023/12/25 08:14:02 > step from ntq to bvb. visited : Set{jqt, xhk, ntq}
+2023/12/25 08:14:02 > step from bvb to ntq. visited : Set{jqt, xhk, ntq, bvb}
+2023/12/25 08:14:02 <<<< cycle true, from bvb to ntq
+2023/12/25 08:14:02 entering remove edge for bvb and ntq
+2023/12/25 08:14:02 removed first [bvb : Set{}]
+2023/12/25 08:14:02 removed second [ntq : Set{jqt, hfx, xhk}]
+2023/12/25 08:14:02 >>>> starting new find cycle
+2023/12/25 08:14:02 initial search from xhk and neighbors Set{hfx, rhn, ntq}
+2023/12/25 08:14:02 initial dfs from xhk to hfx with initial visited Set{xhk}
+2023/12/25 08:14:02 > step from xhk to hfx. visited : Set{xhk}
+2023/12/25 08:14:02 > step from hfx to xhk. visited : Set{xhk, hfx}
+2023/12/25 08:14:02 <<<< cycle true, from hfx to xhk
+2023/12/25 08:14:02 entering remove edge for hfx and xhk
+2023/12/25 08:14:02 removed first [hfx : Set{ntq, rhn, pzl}]
+2023/12/25 08:14:02 removed second [xhk : Set{rhn, ntq}]
+2023/12/25 08:14:02 >>>> starting new find cycle
+2023/12/25 08:14:02 initial search from lsr and neighbors Set{lhk, rzs}
+2023/12/25 08:14:02 initial dfs from lsr to rzs with initial visited Set{lsr}
+2023/12/25 08:14:02 > step from lsr to rzs. visited : Set{lsr}
+2023/12/25 08:14:02 > step from rzs to qnr. visited : Set{lsr, rzs}
+2023/12/25 08:14:02 > step from qnr to rzs. visited : Set{lsr, rzs, qnr}
+2023/12/25 08:14:02 <<<< cycle true, from qnr to rzs
+2023/12/25 08:14:02 entering remove edge for qnr and rzs
+2023/12/25 08:14:02 removed first [qnr : Set{frs, nvd}]
+2023/12/25 08:14:02 removed second [rzs : Set{cmg, lsr, rsh}]
+2023/12/25 08:14:02 >>>> starting new find cycle
+2023/12/25 08:14:02 initial search from pzl and neighbors Set{lsr, hfx, nvd}
+2023/12/25 08:14:02 initial dfs from pzl to lsr with initial visited Set{pzl}
+2023/12/25 08:14:02 > step from pzl to lsr. visited : Set{pzl}
+2023/12/25 08:14:02 > step from lsr to lhk. visited : Set{pzl, lsr}
+2023/12/25 08:14:02 > step from lhk to lsr. visited : Set{lsr, lhk, pzl}
+2023/12/25 08:14:02 <<<< cycle true, from lhk to lsr
+2023/12/25 08:14:02 entering remove edge for lhk and lsr
+2023/12/25 08:14:02 removed first [lhk : Set{frs}]
+2023/12/25 08:14:02 removed second [lsr : Set{rzs}]
+2023/12/25 08:14:02 >>>> starting new find cycle
+2023/12/25 08:14:02 initial search from rhn and neighbors Set{xhk, bvb, hfx}
+2023/12/25 08:14:02 initial dfs from rhn to xhk with initial visited Set{rhn}
+2023/12/25 08:14:02 > step from rhn to xhk. visited : Set{rhn}
+2023/12/25 08:14:02 > step from xhk to rhn. visited : Set{xhk, rhn}
+2023/12/25 08:14:02 <<<< cycle true, from xhk to rhn
+2023/12/25 08:14:02 entering remove edge for xhk and rhn
+2023/12/25 08:14:02 removed first [xhk : Set{ntq}]
+2023/12/25 08:14:02 removed second [rhn : Set{bvb, hfx}]
+2023/12/25 08:14:02 >>>> starting new find cycle
+2023/12/25 08:14:02 initial search from rsh and neighbors Set{frs, pzl, lsr, rzs}
+2023/12/25 08:14:02 initial dfs from rsh to frs with initial visited Set{rsh}
+2023/12/25 08:14:02 > step from rsh to frs. visited : Set{rsh}
+2023/12/25 08:14:02 > step from frs to qnr. visited : Set{rsh, frs}
+2023/12/25 08:14:02 > step from qnr to frs. visited : Set{rsh, frs, qnr}
+2023/12/25 08:14:02 <<<< cycle true, from qnr to frs
+2023/12/25 08:14:02 entering remove edge for qnr and frs
+2023/12/25 08:14:02 removed first [qnr : Set{nvd}]
+2023/12/25 08:14:02 removed second [frs : Set{lhk}]
+2023/12/25 08:14:02 >>>> starting new find cycle
+2023/12/25 08:14:02 initial search from rhn and neighbors Set{bvb, hfx}
+2023/12/25 08:14:02 initial dfs from rhn to hfx with initial visited Set{rhn}
+2023/12/25 08:14:02 > step from rhn to hfx. visited : Set{rhn}
+2023/12/25 08:14:02 > step from hfx to rhn. visited : Set{rhn, hfx}
+2023/12/25 08:14:02 <<<< cycle true, from hfx to rhn
+2023/12/25 08:14:02 entering remove edge for hfx and rhn
+2023/12/25 08:14:02 removed first [hfx : Set{pzl, ntq}]
+2023/12/25 08:14:02 removed second [rhn : Set{bvb}]
+2023/12/25 08:14:02 >>>> starting new find cycle
+2023/12/25 08:14:02 initial search from pzl and neighbors Set{hfx, nvd, lsr}
+2023/12/25 08:14:02 initial dfs from pzl to lsr with initial visited Set{pzl}
+2023/12/25 08:14:02 > step from pzl to lsr. visited : Set{pzl}
+2023/12/25 08:14:02 > step from lsr to rzs. visited : Set{pzl, lsr}
+2023/12/25 08:14:02 > step from rzs to cmg. visited : Set{pzl, lsr, rzs}
+2023/12/25 08:14:02 > step from cmg to rzs. visited : Set{pzl, lsr, rzs, cmg}
+2023/12/25 08:14:02 <<<< cycle true, from cmg to rzs
+2023/12/25 08:14:02 entering remove edge for cmg and rzs
+2023/12/25 08:14:02 removed first [cmg : Set{nvd, bvb}]
+2023/12/25 08:14:02 removed second [rzs : Set{lsr, rsh}]
+2023/12/25 08:14:02 >>>> starting new find cycle
+2023/12/25 08:14:02 initial search from rhn and neighbors Set{bvb}
+2023/12/25 08:14:02 initial dfs from rhn to bvb with initial visited Set{rhn}
+2023/12/25 08:14:02 > step from rhn to bvb. visited : Set{rhn}
+2023/12/25 08:14:02 <<<< cycle false, from  to
+    graph_test.go:57: removed edges Set{{lhk nvd}, {hfx xhk}, {frs qnr}, {cmg rzs}, {bvb xhk}, {bvb hfx}, {cmg qnr}, {cmg lhk}, {qnr rzs}, {hfx rhn}, {frs lsr}, {rhn xhk}, {bvb ntq}, {lhk lsr}}
+    graph_test.go:58: after removal graph is {Nodes:map[bvb:[bvb : Set{}] cmg:[cmg : Set{nvd, bvb}] frs:[frs : Set{lhk}] hfx:[hfx : Set{pzl, ntq}] jqt:[jqt : Set{rhn, xhk, nvd, ntq}] lhk:[lhk : Set{frs}] lsr:[lsr : Set{rzs}] ntq:[ntq : Set{xhk, jqt, hfx}] nvd:[nvd : Set{}] pzl:[pzl : Set{nvd, lsr, hfx}] qnr:[qnr : Set{nvd}] rhn:[rhn : Set{bvb}] rsh:[rsh : Set{frs, pzl, lsr, rzs}] rzs:[rzs : Set{lsr, rsh}] xhk:[xhk : Set{ntq}]]}
+--- PASS: TestRemoveAllCycles (0.00s)
+
+#+end_src
+*** because i was overwriting nodes on file read
+** now why i get empty sets?
+#+begin_src
+=== RUN   TestRemoveAllCycles
+    graph_test.go:55: initial graph is {Nodes:map[bvb:[bvb : Set{cmg, rhn, xhk, hfx, ntq}] cmg:[cmg : Set{lhk, bvb, rzs, qnr, nvd}] frs:[frs : Set{rsh, qnr, lhk, lsr}] hfx:[hfx : Set{xhk, rhn, bvb, pzl, ntq}] jqt:[jqt : Set{rhn, xhk, nvd, ntq}] lhk:[lhk : Set{nvd, lsr, frs, cmg}] lsr:[lsr : Set{rsh, pzl, lhk, rzs, frs}] ntq:[ntq : Set{jqt, hfx, bvb, xhk}] nvd:[nvd : Set{pzl, qnr, lhk, jqt, cmg}] pzl:[pzl : Set{hfx, nvd, rsh, lsr}] qnr:[qnr : Set{cmg, nvd, rzs, frs}] rhn:[rhn : Set{jqt, xhk, bvb, hfx}] rsh:[rsh : Set{lsr, rzs, frs, pzl}] rzs:[rzs : Set{qnr, cmg, lsr, rsh}] xhk:[xhk : Set{hfx, rhn, bvb, ntq, jqt}]]}
+2023/12/25 08:31:09 >>>> starting new find cycle
+2023/12/25 08:31:09 initial search from xhk and neighbors Set{rhn, bvb, ntq, jqt, hfx}
+2023/12/25 08:31:09 initial dfs from xhk to rhn with initial visited Set{xhk}
+2023/12/25 08:31:09 > step from xhk to rhn. visited : Set{xhk}
+2023/12/25 08:31:09 > step from rhn to jqt. visited : Set{xhk, rhn}
+2023/12/25 08:31:09 > step from jqt to rhn. visited : Set{xhk, rhn, jqt}
+2023/12/25 08:31:09 <<<< cycle true, from jqt to rhn
+2023/12/25 08:31:09 entering remove edge for jqt and rhn
+2023/12/25 08:31:09 before remove first [jqt : Set{xhk, nvd, ntq, rhn}]
+2023/12/25 08:31:09 removed first [jqt : Set{ntq, xhk, nvd}]
+2023/12/25 08:31:09 before remove second [jqt : Set{nvd, ntq, xhk}]
+2023/12/25 08:31:09 removed second [rhn : Set{hfx, xhk, bvb}]
+2023/12/25 08:31:09 >>>> starting new find cycle
+2023/12/25 08:31:09 initial search from pzl and neighbors Set{hfx, nvd, rsh, lsr}
+2023/12/25 08:31:09 initial dfs from pzl to nvd with initial visited Set{pzl}
+2023/12/25 08:31:09 > step from pzl to nvd. visited : Set{pzl}
+2023/12/25 08:31:09 > step from nvd to jqt. visited : Set{pzl, nvd}
+2023/12/25 08:31:09 > step from jqt to ntq. visited : Set{pzl, nvd, jqt}
+2023/12/25 08:31:09 > step from ntq to xhk. visited : Set{pzl, nvd, jqt, ntq}
+2023/12/25 08:31:09 > step from xhk to jqt. visited : Set{ntq, pzl, nvd, jqt, xhk}
+2023/12/25 08:31:09 <<<< cycle true, from xhk to jqt
+2023/12/25 08:31:09 entering remove edge for xhk and jqt
+2023/12/25 08:31:09 before remove first [xhk : Set{jqt, hfx, rhn, bvb, ntq}]
+2023/12/25 08:31:09 removed first [xhk : Set{ntq, hfx, rhn, bvb}]
+2023/12/25 08:31:09 before remove second [xhk : Set{hfx, rhn, bvb, ntq}]
+2023/12/25 08:31:09 removed second [jqt : Set{nvd, ntq}]
+2023/12/25 08:31:09 >>>> starting new find cycle
+2023/12/25 08:31:09 initial search from frs and neighbors Set{rsh, qnr, lhk, lsr}
+2023/12/25 08:31:09 initial dfs from frs to lhk with initial visited Set{frs}
+2023/12/25 08:31:09 > step from frs to lhk. visited : Set{frs}
+2023/12/25 08:31:09 > step from lhk to nvd. visited : Set{frs, lhk}
+2023/12/25 08:31:09 > step from nvd to cmg. visited : Set{lhk, frs, nvd}
+2023/12/25 08:31:09 > step from cmg to lhk. visited : Set{frs, nvd, lhk, cmg}
+2023/12/25 08:31:09 <<<< cycle true, from cmg to lhk
+2023/12/25 08:31:09 entering remove edge for cmg and lhk
+2023/12/25 08:31:09 before remove first [cmg : Set{qnr, nvd, lhk, bvb, rzs}]
+2023/12/25 08:31:09 removed first [cmg : Set{nvd, bvb, rzs, qnr}]
+2023/12/25 08:31:09 before remove second [cmg : Set{bvb, rzs, qnr, nvd}]
+2023/12/25 08:31:09 removed second [lhk : Set{nvd, lsr, frs}]
+2023/12/25 08:31:09 >>>> starting new find cycle
+2023/12/25 08:31:09 initial search from xhk and neighbors Set{hfx, rhn, bvb, ntq}
+2023/12/25 08:31:09 initial dfs from xhk to ntq with initial visited Set{xhk}
+2023/12/25 08:31:09 > step from xhk to ntq. visited : Set{xhk}
+2023/12/25 08:31:09 > step from ntq to jqt. visited : Set{xhk, ntq}
+2023/12/25 08:31:09 > step from jqt to ntq. visited : Set{xhk, ntq, jqt}
+2023/12/25 08:31:09 <<<< cycle true, from jqt to ntq
+2023/12/25 08:31:09 entering remove edge for jqt and ntq
+2023/12/25 08:31:09 before remove first [jqt : Set{ntq, nvd}]
+2023/12/25 08:31:09 removed first [jqt : Set{nvd}]
+2023/12/25 08:31:09 before remove second [jqt : Set{nvd}]
+2023/12/25 08:31:09 removed second [ntq : Set{xhk, hfx, bvb}]
+2023/12/25 08:31:09 >>>> starting new find cycle
+2023/12/25 08:31:09 initial search from nvd and neighbors Set{jqt, cmg, pzl, qnr, lhk}
+2023/12/25 08:31:09 initial dfs from nvd to cmg with initial visited Set{nvd}
+2023/12/25 08:31:09 > step from nvd to cmg. visited : Set{nvd}
+2023/12/25 08:31:09 > step from cmg to bvb. visited : Set{nvd, cmg}
+2023/12/25 08:31:09 > step from bvb to cmg. visited : Set{cmg, nvd, bvb}
+2023/12/25 08:31:09 <<<< cycle true, from bvb to cmg
+2023/12/25 08:31:09 entering remove edge for bvb and cmg
+2023/12/25 08:31:09 before remove first [bvb : Set{cmg, rhn, xhk, hfx, ntq}]
+2023/12/25 08:31:09 removed first [bvb : Set{xhk, hfx, ntq, rhn}]
+2023/12/25 08:31:09 before remove second [bvb : Set{rhn, xhk, hfx, ntq}]
+2023/12/25 08:31:09 removed second [cmg : Set{rzs, qnr, nvd}]
+2023/12/25 08:31:09 >>>> starting new find cycle
+2023/12/25 08:31:09 initial search from frs and neighbors Set{rsh, qnr, lhk, lsr}
+2023/12/25 08:31:09 initial dfs from frs to lsr with initial visited Set{frs}
+2023/12/25 08:31:09 > step from frs to lsr. visited : Set{frs}
+2023/12/25 08:31:09 > step from lsr to rzs. visited : Set{frs, lsr}
+2023/12/25 08:31:09 > step from rzs to cmg. visited : Set{frs, lsr, rzs}
+2023/12/25 08:31:09 > step from cmg to rzs. visited : Set{lsr, rzs, cmg, frs}
+2023/12/25 08:31:09 <<<< cycle true, from cmg to rzs
+2023/12/25 08:31:09 entering remove edge for cmg and rzs
+2023/12/25 08:31:09 before remove first [cmg : Set{rzs, qnr, nvd}]
+2023/12/25 08:31:09 removed first [cmg : Set{qnr, nvd}]
+2023/12/25 08:31:09 before remove second [cmg : Set{qnr, nvd}]
+2023/12/25 08:31:09 removed second [rzs : Set{lsr, rsh, qnr}]
+2023/12/25 08:31:09 >>>> starting new find cycle
+2023/12/25 08:31:09 initial search from ntq and neighbors Set{xhk, hfx, bvb}
+2023/12/25 08:31:09 initial dfs from ntq to bvb with initial visited Set{ntq}
+2023/12/25 08:31:09 > step from ntq to bvb. visited : Set{ntq}
+2023/12/25 08:31:09 > step from bvb to rhn. visited : Set{ntq, bvb}
+2023/12/25 08:31:09 > step from rhn to xhk. visited : Set{bvb, ntq, rhn}
+2023/12/25 08:31:09 > step from xhk to hfx. visited : Set{bvb, ntq, rhn, xhk}
+2023/12/25 08:31:09 > step from hfx to bvb. visited : Set{xhk, bvb, ntq, rhn, hfx}
+2023/12/25 08:31:09 <<<< cycle true, from hfx to bvb
+2023/12/25 08:31:09 entering remove edge for hfx and bvb
+2023/12/25 08:31:09 before remove first [hfx : Set{rhn, bvb, pzl, ntq, xhk}]
+2023/12/25 08:31:09 removed first [hfx : Set{ntq, xhk, rhn, pzl}]
+2023/12/25 08:31:09 before remove second [hfx : Set{pzl, ntq, xhk, rhn}]
+2023/12/25 08:31:09 removed second [bvb : Set{ntq, rhn, xhk}]
+2023/12/25 08:31:09 >>>> starting new find cycle
+2023/12/25 08:31:09 initial search from rhn and neighbors Set{xhk, bvb, hfx}
+2023/12/25 08:31:09 initial dfs from rhn to bvb with initial visited Set{rhn}
+2023/12/25 08:31:09 > step from rhn to bvb. visited : Set{rhn}
+2023/12/25 08:31:09 > step from bvb to rhn. visited : Set{bvb, rhn}
+2023/12/25 08:31:09 <<<< cycle true, from bvb to rhn
+2023/12/25 08:31:09 entering remove edge for bvb and rhn
+2023/12/25 08:31:09 before remove first [bvb : Set{ntq, rhn, xhk}]
+2023/12/25 08:31:09 removed first [bvb : Set{ntq, xhk}]
+2023/12/25 08:31:09 before remove second [bvb : Set{ntq, xhk}]
+2023/12/25 08:31:09 removed second [rhn : Set{xhk, hfx}]
+2023/12/25 08:31:09 >>>> starting new find cycle
+2023/12/25 08:31:09 initial search from rhn and neighbors Set{xhk, hfx}
+2023/12/25 08:31:09 initial dfs from rhn to hfx with initial visited Set{rhn}
+2023/12/25 08:31:09 > step from rhn to hfx. visited : Set{rhn}
+2023/12/25 08:31:09 > step from hfx to pzl. visited : Set{rhn, hfx}
+2023/12/25 08:31:09 > step from pzl to rsh. visited : Set{rhn, hfx, pzl}
+2023/12/25 08:31:09 > step from rsh to frs. visited : Set{hfx, pzl, rsh, rhn}
+2023/12/25 08:31:09 > step from frs to qnr. visited : Set{rsh, frs, rhn, hfx, pzl}
+2023/12/25 08:31:09 > step from qnr to cmg. visited : Set{rsh, frs, rhn, hfx, pzl, qnr}
+2023/12/25 08:31:09 > step from cmg to qnr. visited : Set{hfx, pzl, qnr, cmg, rsh, frs, rhn}
+2023/12/25 08:31:09 <<<< cycle true, from cmg to qnr
+2023/12/25 08:31:09 entering remove edge for cmg and qnr
+2023/12/25 08:31:09 before remove first [cmg : Set{qnr, nvd}]
+2023/12/25 08:31:09 removed first [cmg : Set{nvd}]
+2023/12/25 08:31:09 before remove second [cmg : Set{nvd}]
+2023/12/25 08:31:09 removed second [qnr : Set{nvd, rzs, frs}]
+2023/12/25 08:31:09 >>>> starting new find cycle
+2023/12/25 08:31:09 initial search from lsr and neighbors Set{rsh, pzl, lhk, rzs, frs}
+2023/12/25 08:31:09 initial dfs from lsr to frs with initial visited Set{lsr}
+2023/12/25 08:31:09 > step from lsr to frs. visited : Set{lsr}
+2023/12/25 08:31:09 > step from frs to rsh. visited : Set{lsr, frs}
+2023/12/25 08:31:09 > step from rsh to frs. visited : Set{lsr, frs, rsh}
+2023/12/25 08:31:09 <<<< cycle true, from rsh to frs
+2023/12/25 08:31:09 entering remove edge for rsh and frs
+2023/12/25 08:31:09 before remove first [rsh : Set{frs, pzl, lsr, rzs}]
+2023/12/25 08:31:09 removed first [rsh : Set{rzs, pzl, lsr}]
+2023/12/25 08:31:09 before remove second [rsh : Set{rzs, pzl, lsr}]
+2023/12/25 08:31:09 removed second [frs : Set{qnr, lhk, lsr}]
+2023/12/25 08:31:09 >>>> starting new find cycle
+2023/12/25 08:31:09 initial search from rhn and neighbors Set{xhk, hfx}
+2023/12/25 08:31:09 initial dfs from rhn to xhk with initial visited Set{rhn}
+2023/12/25 08:31:09 > step from rhn to xhk. visited : Set{rhn}
+2023/12/25 08:31:09 > step from xhk to hfx. visited : Set{rhn, xhk}
+2023/12/25 08:31:09 > step from hfx to pzl. visited : Set{rhn, xhk, hfx}
+2023/12/25 08:31:09 > step from pzl to rsh. visited : Set{rhn, xhk, hfx, pzl}
+2023/12/25 08:31:09 > step from rsh to rzs. visited : Set{rhn, xhk, hfx, pzl, rsh}
+2023/12/25 08:31:09 > step from rzs to rsh. visited : Set{rzs, rsh, rhn, xhk, hfx, pzl}
+2023/12/25 08:31:09 <<<< cycle true, from rzs to rsh
+2023/12/25 08:31:09 entering remove edge for rzs and rsh
+2023/12/25 08:31:09 before remove first [rzs : Set{lsr, rsh, qnr}]
+2023/12/25 08:31:09 removed first [rzs : Set{qnr, lsr}]
+2023/12/25 08:31:09 before remove second [rzs : Set{lsr, qnr}]
+2023/12/25 08:31:09 removed second [rsh : Set{pzl, lsr}]
+2023/12/25 08:31:09 >>>> starting new find cycle
+2023/12/25 08:31:09 initial search from xhk and neighbors Set{hfx, rhn, bvb, ntq}
+2023/12/25 08:31:09 initial dfs from xhk to hfx with initial visited Set{xhk}
+2023/12/25 08:31:09 > step from xhk to hfx. visited : Set{xhk}
+2023/12/25 08:31:09 > step from hfx to pzl. visited : Set{xhk, hfx}
+2023/12/25 08:31:09 > step from pzl to rsh. visited : Set{xhk, hfx, pzl}
+2023/12/25 08:31:09 > step from rsh to pzl. visited : Set{pzl, xhk, hfx, rsh}
+2023/12/25 08:31:09 <<<< cycle true, from rsh to pzl
+2023/12/25 08:31:09 entering remove edge for rsh and pzl
+2023/12/25 08:31:09 before remove first [rsh : Set{pzl, lsr}]
+2023/12/25 08:31:09 removed first [rsh : Set{lsr}]
+2023/12/25 08:31:09 before remove second [rsh : Set{lsr}]
+2023/12/25 08:31:09 removed second [pzl : Set{lsr, hfx, nvd}]
+2023/12/25 08:31:09 >>>> starting new find cycle
+2023/12/25 08:31:09 initial search from rsh and neighbors Set{lsr}
+2023/12/25 08:31:09 initial dfs from rsh to lsr with initial visited Set{rsh}
+2023/12/25 08:31:09 > step from rsh to lsr. visited : Set{rsh}
+2023/12/25 08:31:09 > step from lsr to frs. visited : Set{rsh, lsr}
+2023/12/25 08:31:09 > step from frs to qnr. visited : Set{frs, lsr, rsh}
+2023/12/25 08:31:09 > step from qnr to nvd. visited : Set{lsr, rsh, frs, qnr}
+2023/12/25 08:31:09 > step from nvd to jqt. visited : Set{rsh, frs, qnr, nvd, lsr}
+2023/12/25 08:31:09 > step from jqt to nvd. visited : Set{lsr, rsh, frs, qnr, nvd, jqt}
+2023/12/25 08:31:09 <<<< cycle true, from jqt to nvd
+2023/12/25 08:31:09 entering remove edge for jqt and nvd
+2023/12/25 08:31:09 before remove first [jqt : Set{nvd}]
+2023/12/25 08:31:09 removed first [jqt : Set{}]
+2023/12/25 08:31:09 before remove second [jqt : Set{}]
+2023/12/25 08:31:09 removed second [nvd : Set{cmg, pzl, qnr, lhk}]
+2023/12/25 08:31:09 >>>> starting new find cycle
+2023/12/25 08:31:09 initial search from bvb and neighbors Set{ntq, xhk}
+2023/12/25 08:31:09 initial dfs from bvb to ntq with initial visited Set{bvb}
+2023/12/25 08:31:09 > step from bvb to ntq. visited : Set{bvb}
+2023/12/25 08:31:09 > step from ntq to xhk. visited : Set{bvb, ntq}
+2023/12/25 08:31:09 > step from xhk to hfx. visited : Set{ntq, xhk, bvb}
+2023/12/25 08:31:09 > step from hfx to pzl. visited : Set{bvb, ntq, xhk, hfx}
+2023/12/25 08:31:09 > step from pzl to nvd. visited : Set{pzl, bvb, ntq, xhk, hfx}
+2023/12/25 08:31:09 > step from nvd to qnr. visited : Set{hfx, pzl, nvd, bvb, ntq, xhk}
+2023/12/25 08:31:09 > step from qnr to nvd. visited : Set{pzl, nvd, bvb, ntq, xhk, hfx, qnr}
+2023/12/25 08:31:09 <<<< cycle true, from qnr to nvd
+2023/12/25 08:31:09 entering remove edge for qnr and nvd
+2023/12/25 08:31:09 before remove first [qnr : Set{nvd, rzs, frs}]
+2023/12/25 08:31:09 removed first [qnr : Set{rzs, frs}]
+2023/12/25 08:31:09 before remove second [qnr : Set{frs, rzs}]
+2023/12/25 08:31:09 removed second [nvd : Set{pzl, lhk, cmg}]
+2023/12/25 08:31:09 >>>> starting new find cycle
+2023/12/25 08:31:09 initial search from pzl and neighbors Set{lsr, hfx, nvd}
+2023/12/25 08:31:09 initial dfs from pzl to lsr with initial visited Set{pzl}
+2023/12/25 08:31:09 > step from pzl to lsr. visited : Set{pzl}
+2023/12/25 08:31:09 > step from lsr to rsh. visited : Set{pzl, lsr}
+2023/12/25 08:31:09 > step from rsh to lsr. visited : Set{pzl, lsr, rsh}
+2023/12/25 08:31:09 <<<< cycle true, from rsh to lsr
+2023/12/25 08:31:09 entering remove edge for rsh and lsr
+2023/12/25 08:31:09 before remove first [rsh : Set{lsr}]
+2023/12/25 08:31:09 removed first [rsh : Set{}]
+2023/12/25 08:31:09 before remove second [rsh : Set{}]
+2023/12/25 08:31:09 removed second [lsr : Set{rzs, frs, pzl, lhk}]
+2023/12/25 08:31:09 >>>> starting new find cycle
+2023/12/25 08:31:09 initial search from rhn and neighbors Set{xhk, hfx}
+2023/12/25 08:31:09 initial dfs from rhn to xhk with initial visited Set{rhn}
+2023/12/25 08:31:09 > step from rhn to xhk. visited : Set{rhn}
+2023/12/25 08:31:09 > step from xhk to hfx. visited : Set{rhn, xhk}
+2023/12/25 08:31:09 > step from hfx to pzl. visited : Set{hfx, rhn, xhk}
+2023/12/25 08:31:09 > step from pzl to lsr. visited : Set{rhn, xhk, hfx, pzl}
+2023/12/25 08:31:09 > step from lsr to frs. visited : Set{xhk, hfx, pzl, rhn, lsr}
+2023/12/25 08:31:09 > step from frs to qnr. visited : Set{rhn, lsr, xhk, hfx, pzl, frs}
+2023/12/25 08:31:09 > step from qnr to rzs. visited : Set{qnr, rhn, lsr, xhk, hfx, pzl, frs}
+2023/12/25 08:31:09 > step from rzs to lsr. visited : Set{hfx, rzs, pzl, frs, qnr, rhn, lsr, xhk}
+2023/12/25 08:31:09 <<<< cycle true, from rzs to lsr
+2023/12/25 08:31:09 entering remove edge for rzs and lsr
+2023/12/25 08:31:09 before remove first [rzs : Set{lsr, qnr}]
+2023/12/25 08:31:09 removed first [rzs : Set{qnr}]
+2023/12/25 08:31:09 before remove second [rzs : Set{qnr}]
+2023/12/25 08:31:09 removed second [lsr : Set{lhk, frs, pzl}]
+2023/12/25 08:31:09 >>>> starting new find cycle
+2023/12/25 08:31:09 initial search from frs and neighbors Set{qnr, lhk, lsr}
+2023/12/25 08:31:09 initial dfs from frs to qnr with initial visited Set{frs}
+2023/12/25 08:31:09 > step from frs to qnr. visited : Set{frs}
+2023/12/25 08:31:09 > step from qnr to rzs. visited : Set{frs, qnr}
+2023/12/25 08:31:09 > step from rzs to qnr. visited : Set{frs, qnr, rzs}
+2023/12/25 08:31:09 <<<< cycle true, from rzs to qnr
+2023/12/25 08:31:09 entering remove edge for rzs and qnr
+2023/12/25 08:31:09 before remove first [rzs : Set{qnr}]
+2023/12/25 08:31:09 removed first [rzs : Set{}]
+2023/12/25 08:31:09 before remove second [rzs : Set{}]
+2023/12/25 08:31:09 removed second [qnr : Set{frs}]
+2023/12/25 08:31:09 >>>> starting new find cycle
+2023/12/25 08:31:09 initial search from frs and neighbors Set{qnr, lhk, lsr}
+2023/12/25 08:31:09 initial dfs from frs to qnr with initial visited Set{frs}
+2023/12/25 08:31:09 > step from frs to qnr. visited : Set{frs}
+2023/12/25 08:31:09 > step from qnr to frs. visited : Set{frs, qnr}
+2023/12/25 08:31:09 <<<< cycle true, from qnr to frs
+2023/12/25 08:31:09 entering remove edge for qnr and frs
+2023/12/25 08:31:09 before remove first [qnr : Set{frs}]
+2023/12/25 08:31:09 removed first [qnr : Set{}]
+2023/12/25 08:31:09 before remove second [qnr : Set{}]
+2023/12/25 08:31:09 removed second [frs : Set{lsr, lhk}]
+2023/12/25 08:31:09 >>>> starting new find cycle
+2023/12/25 08:31:09 initial search from frs and neighbors Set{lsr, lhk}
+2023/12/25 08:31:09 initial dfs from frs to lhk with initial visited Set{frs}
+2023/12/25 08:31:09 > step from frs to lhk. visited : Set{frs}
+2023/12/25 08:31:09 > step from lhk to nvd. visited : Set{frs, lhk}
+2023/12/25 08:31:09 > step from nvd to cmg. visited : Set{lhk, nvd, frs}
+2023/12/25 08:31:09 > step from cmg to nvd. visited : Set{nvd, cmg, frs, lhk}
+2023/12/25 08:31:09 <<<< cycle true, from cmg to nvd
+2023/12/25 08:31:09 entering remove edge for cmg and nvd
+2023/12/25 08:31:09 before remove first [cmg : Set{nvd}]
+2023/12/25 08:31:09 removed first [cmg : Set{}]
+2023/12/25 08:31:09 before remove second [cmg : Set{}]
+2023/12/25 08:31:09 removed second [nvd : Set{pzl, lhk}]
+2023/12/25 08:31:09 >>>> starting new find cycle
+2023/12/25 08:31:09 initial search from cmg and neighbors Set{}
+2023/12/25 08:31:09 <<<< cycle false, from  to
+    graph_test.go:57: removed edges Set{{frs qnr}, {cmg lhk}, {bvb cmg}, {bvb rhn}, {lsr rzs}, {jqt nvd}, {nvd qnr}, {cmg nvd}, {jqt rhn}, {cmg rzs}, {frs rsh}, {rsh rzs}, {jqt ntq}, {cmg qnr}, {lsr rsh}, {jqt xhk}, {bvb hfx}, {pzl rsh}, {qnr rzs}}
+    graph_test.go:58: after removal graph is {Nodes:map[bvb:[bvb : Set{ntq, xhk}] cmg:[cmg : Set{}] frs:[frs : Set{lhk, lsr}] hfx:[hfx : Set{rhn, pzl, ntq, xhk}] jqt:[jqt : Set{}] lhk:[lhk : Set{nvd, lsr, frs}] lsr:[lsr : Set{frs, pzl, lhk}] ntq:[ntq : Set{bvb, xhk, hfx}] nvd:[nvd : Set{pzl, lhk}] pzl:[pzl : Set{lsr, hfx, nvd}] qnr:[qnr : Set{}] rhn:[rhn : Set{xhk, hfx}] rsh:[rsh : Set{}] rzs:[rzs : Set{}] xhk:[xhk : Set{ntq, hfx, rhn, bvb}]]}
+--- PASS: TestRemoveAllCycles (0.00s)
+PASS
+ok  	sunshine.industries/aoc2023/day25	0.003s
+
+#+end_src
+** kind of bruteforce
+    graph_test.go:93: hopefully as answer: 0
+    graph_test.go:93: hopefully as answer: 0
+    graph_test.go:93: hopefully as answer: 0
+    graph_test.go:93: hopefully as answer: 0
+    graph_test.go:93: hopefully as answer: 0
+    graph_test.go:93: hopefully as answer: 0
+    graph_test.go:93: hopefully as answer: 0
+    graph_test.go:93: hopefully as answer: 0
+    graph_test.go:93: hopefully as answer: 0
+    graph_test.go:93: hopefully as answer: 0
+    graph_test.go:93: hopefully as answer: 0
+    graph_test.go:93: hopefully as answer: 0
+    graph_test.go:93: hopefully as answer: 0
+    graph_test.go:93: hopefully as answer: 0
+    graph_test.go:93: hopefully as answer: 0
+    graph_test.go:93: hopefully as answer: 0
+    graph_test.go:93: hopefully as answer: 0
+    graph_test.go:93: hopefully as answer: 518391
+    graph_test.go:93: hopefully as answer: 0
+    graph_test.go:93: hopefully as answer: 518391
+    graph_test.go:93: hopefully as answer: 0

main.go

@@ -4,15 +4,15 @@ import (
 	"log"
 	"time"
 
-	"sunshine.industries/aoc2023/day24"
+	"sunshine.industries/aoc2023/day25"
 )
 
 func main() {
 	startTime := time.Now()
 	log.Print("> starting run:")
 
-	result := day24.Run()
-	log.Printf("\n\nday24 result: %d\n****\n", result)
+	result := day25.Run()
+	log.Printf("\n\nday25 result: %d\n****\n", result)
 	endTime := time.Now()
 	diff := endTime.Sub(startTime)
 	log.Printf("execution took %s", diff.String())