diff --git a/d05/main.go b/d05/main.go
index c1d6e1c..95214a0 100644
--- a/d05/main.go
+++ b/d05/main.go
@@ -45,7 +45,7 @@ ItemLoop:
 
 func part2(data []string) int {
 	niceStringsCount := 0
-	alphabetCombinations := util.ArrayMap(util.Combinations(util.AlphabetArray[:]), func(combination []string) string {
+	alphabetCombinations := util.ArrayMap(util.Doubles(util.AlphabetArray[:]), func(combination []string) string {
 		return fmt.Sprintf("%s%s", combination[0], combination[1])
 	})
 
diff --git a/d09/input.txt b/d09/input.txt
new file mode 100644
index 0000000..38d4369
--- /dev/null
+++ b/d09/input.txt
@@ -0,0 +1,28 @@
+Faerun to Norrath = 129
+Faerun to Tristram = 58
+Faerun to AlphaCentauri = 13
+Faerun to Arbre = 24
+Faerun to Snowdin = 60
+Faerun to Tambi = 71
+Faerun to Straylight = 67
+Norrath to Tristram = 142
+Norrath to AlphaCentauri = 15
+Norrath to Arbre = 135
+Norrath to Snowdin = 75
+Norrath to Tambi = 82
+Norrath to Straylight = 54
+Tristram to AlphaCentauri = 118
+Tristram to Arbre = 122
+Tristram to Snowdin = 103
+Tristram to Tambi = 49
+Tristram to Straylight = 97
+AlphaCentauri to Arbre = 116
+AlphaCentauri to Snowdin = 12
+AlphaCentauri to Tambi = 18
+AlphaCentauri to Straylight = 91
+Arbre to Snowdin = 129
+Arbre to Tambi = 53
+Arbre to Straylight = 40
+Snowdin to Tambi = 15
+Snowdin to Straylight = 99
+Tambi to Straylight = 70
\ No newline at end of file
diff --git a/d09/main.go b/d09/main.go
new file mode 100644
index 0000000..38c35cf
--- /dev/null
+++ b/d09/main.go
@@ -0,0 +1,100 @@
+package main
+
+import (
+	"aoc2015/util"
+	"regexp"
+	"slices"
+
+	mapset "github.com/deckarep/golang-set/v2"
+	"github.com/dominikbraun/graph"
+)
+
+type Route struct {
+	From, To string
+	Distance int
+}
+
+func getUniqueDestinations(data []Route) []string {
+	uniqueDestinations := mapset.NewSet[string]()
+
+	for _, route := range data {
+		uniqueDestinations.Add(route.From)
+		uniqueDestinations.Add(route.To)
+	}
+
+	return uniqueDestinations.ToSlice()
+}
+
+func calculateDistances(data []Route) []int {
+	destinations := getUniqueDestinations(data)
+	g := graph.New(graph.StringHash, graph.Weighted())
+
+	for _, destination := range destinations {
+		g.AddVertex(destination)
+	}
+
+	for _, route := range data {
+		g.AddEdge(route.From, route.To, graph.EdgeWeight(route.Distance))
+	}
+
+	spanningPaths := [][]string{}
+
+	for _, departure := range destinations {
+		for _, destination := range destinations {
+			if departure == destination {
+				continue
+			}
+
+			paths, _ := graph.AllPathsBetween(g, departure, destination)
+
+			for _, path := range paths {
+				if len(path) == len(destinations) {
+					spanningPaths = append(spanningPaths, path)
+				}
+			}
+		}
+	}
+
+	return util.ArrayMap(spanningPaths, func(spanningPath []string) int {
+		distance := 0
+		for i := 0; i < len(spanningPath)-1; i++ {
+			from := spanningPath[i]
+			to := spanningPath[i+1]
+			edge, _ := g.Edge(from, to)
+
+			distance += edge.Properties.Weight
+		}
+
+		return distance
+	})
+}
+
+func part1(data []Route) int {
+	distances := calculateDistances(data)
+
+	return slices.Min(distances)
+}
+
+func part2(data []Route) int {
+	distances := calculateDistances(data)
+
+	return slices.Max(distances)
+}
+
+func main() {
+	lineRegexp := regexp.MustCompile(`(\w+) to (\w+) = (\d+)`)
+	reader := func(name string) []Route {
+		return util.ArrayMap(util.ReadLines(name), func(line string) Route {
+			match := lineRegexp.FindStringSubmatch(line)
+
+			return Route{
+				From:     match[1],
+				To:       match[2],
+				Distance: util.StringToInt(match[3]),
+			}
+		})
+	}
+
+	util.TestRuns("09", reader, part1, part2)
+	util.SolutionRuns("09", reader, part1, part2)
+}
diff --git a/d09/test-runs/0.txt b/d09/test-runs/0.txt
new file mode 100644
index 0000000..d8224f9
--- /dev/null
+++ b/d09/test-runs/0.txt
@@ -0,0 +1,3 @@
+London to Dublin = 464
+London to Belfast = 518
+Dublin to Belfast = 141
\ No newline at end of file
diff --git a/go.mod b/go.mod
index 27c3b12..992d1fb 100644
--- a/go.mod
+++ b/go.mod
@@ -4,14 +4,14 @@ go 1.23.2
 
 require (
 	github.com/deckarep/golang-set/v2 v2.6.0
+	github.com/dominikbraun/graph v0.23.0
 	github.com/fatih/color v1.18.0
+	github.com/mxschmitt/golang-combinations v1.2.0
 	golang.org/x/exp v0.0.0-20241009180824-f66d83c29e7c
 )
 
 require (
 	github.com/mattn/go-colorable v0.1.13 // indirect
 	github.com/mattn/go-isatty v0.0.20 // indirect
-	github.com/mxschmitt/golang-combinations v1.2.0 // indirect
 	golang.org/x/sys v0.25.0 // indirect
-	gonum.org/v1/gonum v0.15.1 // indirect
 )
diff --git a/go.sum b/go.sum
index b64eb7d..6f49f3a 100644
--- a/go.sum
+++ b/go.sum
@@ -1,5 +1,7 @@
 github.com/deckarep/golang-set/v2 v2.6.0 h1:XfcQbWM1LlMB8BsJ8N9vW5ehnnPVIw0je80NsVHagjM=
 github.com/deckarep/golang-set/v2 v2.6.0/go.mod h1:VAky9rY/yGXJOLEDv3OMci+7wtDpOF4IN+y82NBOac4=
+github.com/dominikbraun/graph v0.23.0 h1:TdZB4pPqCLFxYhdyMFb1TBdFxp8XLcJfTTBQucVPgCo=
+github.com/dominikbraun/graph v0.23.0/go.mod h1:yOjYyogZLY1LSG9E33JWZJiq5k83Qy2C6POAuiViluc=
 github.com/fatih/color v1.18.0 h1:S8gINlzdQ840/4pfAwic/ZE0djQEH3wM94VfqLTZcOM=
 github.com/fatih/color v1.18.0/go.mod h1:4FelSpRwEGDpQ12mAdzqdOukCy4u8WUtOY6lkT/6HfU=
 github.com/mattn/go-colorable v0.1.13 h1:fFA4WZxdEF4tXPZVKMLwD8oUnCTTo08duU7wxecdEvA=
@@ -15,5 +17,3 @@ golang.org/x/sys v0.0.0-20220811171246-fbc7d0a398ab/go.mod h1:oPkhp1MJrh7nUepCBc
 golang.org/x/sys v0.6.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.25.0 h1:r+8e+loiHxRqhXVl6ML1nO3l1+oFoWbnlu2Ehimmi34=
 golang.org/x/sys v0.25.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
-gonum.org/v1/gonum v0.15.1 h1:FNy7N6OUZVUaWG9pTiD+jlhdQ3lMP+/LcTpJ6+a8sQ0=
-gonum.org/v1/gonum v0.15.1/go.mod h1:eZTZuRFrzu5pcyjN5wJhcIhnUdNijYxX1T2IcrOGY0o=