diff --git a/bfs.go b/bfs.go
index 91fe3d0..c364d51 100644
--- a/bfs.go
+++ b/bfs.go
@@ -7,17 +7,20 @@ package graph
 func BFS(g Iterator, v int, do func(v, w int, c int64)) {
 	visited := make([]bool, g.Order())
 	visited[v] = true
-	for queue := []int{v}; len(queue) > 0; {
-		v := queue[0]
-		queue = queue[1:]
-		g.Visit(v, func(w int, c int64) (skip bool) {
-			if visited[w] {
-				return
-			}
-			do(v, w, c)
-			visited[w] = true
-			queue = append(queue, w)
+	queue := []int{v}
+
+	fn := func(w int, c int64) (skip bool) {
+		if visited[w] {
 			return
-		})
+		}
+		do(v, w, c)
+		visited[w] = true
+		queue = append(queue, w)
+		return
+	}
+	for len(queue) > 0 {
+		v = queue[0]
+		queue = queue[1:]
+		g.Visit(v, fn)
 	}
 }
diff --git a/bfs_test.go b/bfs_test.go
index a7f5a45..c54c46f 100644
--- a/bfs_test.go
+++ b/bfs_test.go
@@ -1,6 +1,7 @@
 package graph
 
 import (
+	"math/rand"
 	"strconv"
 	"testing"
 )
@@ -26,3 +27,19 @@ func TestBFS(t *testing.T) {
 		t.Errorf("BFS: %s", mess)
 	}
 }
+
+func BenchmarkBFS(b *testing.B) {
+	n := 1000
+	g := New(n)
+	for i := 0; i < 5*n; i++ {
+		g.AddBoth(rand.Intn(n), rand.Intn(n))
+	}
+
+	fn := func(v, w int, c int64) {}
+
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		BFS(g, 0, fn)
+	}
+}
diff --git a/bipart.go b/bipart.go
index 566157e..d02697e 100644
--- a/bipart.go
+++ b/bipart.go
@@ -12,31 +12,36 @@ func Bipartition(g Iterator) (part []int, ok bool) {
 	)
 	colors := make([]color, g.Order())
 	whiteCount := 0
+
+	var src int
+	var queue []int
+	do := func(w int, _ int64) (skip bool) {
+		v := src
+		switch {
+		case colors[w] != none:
+			if colors[v] == colors[w] {
+				skip = true
+			}
+			return
+		case colors[v] == white:
+			colors[w] = black
+		default:
+			colors[w] = white
+			whiteCount++
+		}
+		queue = append(queue, w)
+		return
+	}
 	for v := range colors {
 		if colors[v] != none {
 			continue
 		}
 		colors[v] = white
 		whiteCount++
-		for queue := []int{v}; len(queue) > 0; {
-			v := queue[0]
+		for queue = []int{v}; len(queue) > 0; {
+			src = queue[0]
 			queue = queue[1:]
-			if g.Visit(v, func(w int, _ int64) (skip bool) {
-				switch {
-				case colors[w] != none:
-					if colors[v] == colors[w] {
-						skip = true
-					}
-					return
-				case colors[v] == white:
-					colors[w] = black
-				default:
-					colors[w] = white
-					whiteCount++
-				}
-				queue = append(queue, w)
-				return
-			}) {
+			if g.Visit(src, do) {
 				return []int{}, false
 			}
 		}
diff --git a/bipart_test.go b/bipart_test.go
index 2b2f644..eb22301 100644
--- a/bipart_test.go
+++ b/bipart_test.go
@@ -1,6 +1,7 @@
 package graph
 
 import (
+	"math/rand"
 	"testing"
 )
 
@@ -93,3 +94,18 @@ func TestBipartition(t *testing.T) {
 		t.Errorf("Bipartition: %s", mess)
 	}
 }
+
+func BenchmarkBipartition(b *testing.B) {
+	n := 1000
+	g := New(n)
+	for i := 0; i < 3*n; i++ {
+		g.AddBoth(rand.Intn(n), rand.Intn(n))
+	}
+	h := Sort(g)
+
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		_, _ = Bipartition(h)
+	}
+}
diff --git a/euler.go b/euler.go
index 52f959a..3fb8fc6 100644
--- a/euler.go
+++ b/euler.go
@@ -6,13 +6,18 @@ func EulerDirected(g Iterator) (walk []int, ok bool) {
 	n := g.Order()
 	degree := make([]int, n) // outdegree - indegree for each vertex
 	edgeCount := 0
+
+	var src int
+	degreeFn := func(w int, _ int64) (skip bool) {
+		v := src
+		edgeCount++
+		degree[v]++
+		degree[w]--
+		return
+	}
 	for v := range degree {
-		g.Visit(v, func(w int, _ int64) (skip bool) {
-			edgeCount++
-			degree[v]++
-			degree[w]--
-			return
-		})
+		src = v
+		g.Visit(src, degreeFn)
 	}
 	if edgeCount == 0 {
 		return []int{}, true
@@ -33,11 +38,14 @@ func EulerDirected(g Iterator) (walk []int, ok bool) {
 
 	// Make a copy of g
 	h := make([][]int, n)
+	copyFn := func(w int, _ int64) (skip bool) {
+		v := src
+		h[v] = append(h[v], w)
+		return
+	}
 	for v := range h {
-		g.Visit(v, func(w int, _ int64) (skip bool) {
-			h[v] = append(h[v], w)
-			return
-		})
+		src = v
+		g.Visit(src, copyFn)
 	}
 
 	// Find a starting point with neighbors.
@@ -77,14 +85,19 @@ func EulerUndirected(g Iterator) (walk []int, ok bool) {
 	n := g.Order()
 	out := make([]int, n) // outdegree for each vertex
 	edgeCount := 0
+
+	var src int
+	outDegreeFn := func(w int, _ int64) (skip bool) {
+		v := src
+		edgeCount++
+		if v != w {
+			out[v]++
+		}
+		return
+	}
 	for v := range out {
-		g.Visit(v, func(w int, _ int64) (skip bool) {
-			edgeCount++
-			if v != w {
-				out[v]++
-			}
-			return
-		})
+		src = v
+		g.Visit(src, outDegreeFn)
 	}
 	if edgeCount == 0 {
 		return []int{}, true
diff --git a/euler_test.go b/euler_test.go
index 193bd1c..60b694d 100644
--- a/euler_test.go
+++ b/euler_test.go
@@ -1,6 +1,7 @@
 package graph
 
 import (
+	"math/rand"
 	"testing"
 )
 
@@ -155,3 +156,39 @@ func TestEulerUndirected(t *testing.T) {
 		t.Errorf("EulerUndirected: %s", mess)
 	}
 }
+
+func BenchmarkEulerDirected(b *testing.B) {
+	n := 100
+	g := New(n)
+	for i := 0; i < n-1; i++ {
+		g.Add(i, i+1)
+	}
+	for i := 0; i < 3*n; i++ {
+		g.Add(rand.Intn(n), rand.Intn(n))
+	}
+	h := Sort(g)
+
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		_, _ = EulerDirected(h)
+	}
+}
+
+func BenchmarkEulerUndirected(b *testing.B) {
+	n := 100
+	g := New(n)
+	for i := 0; i < n-1; i++ {
+		g.AddBoth(i, i+1)
+	}
+	for i := 0; i < 3*n; i++ {
+		g.Add(rand.Intn(n), rand.Intn(n))
+	}
+	h := Sort(g)
+
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		_, _ = EulerUndirected(h)
+	}
+}
diff --git a/immutable.go b/immutable.go
index 8f66979..e547e76 100644
--- a/immutable.go
+++ b/immutable.go
@@ -41,18 +41,21 @@ func Transpose(g Iterator) *Immutable {
 func build(g Iterator, transpose bool) *Immutable {
 	n := g.Order()
 	h := &Immutable{edges: make([][]neighbor, n)}
-	for v := range h.edges {
-		g.Visit(v, func(w int, c int64) (skip bool) {
-			if w < 0 || w >= n {
-				panic("vertex out of range: " + strconv.Itoa(w))
-			}
-			if transpose {
-				h.edges[w] = append(h.edges[w], neighbor{v, c})
-			} else {
-				h.edges[v] = append(h.edges[v], neighbor{w, c})
-			}
-			return
-		})
+
+	var v int
+	do := func(w int, c int64) (skip bool) {
+		if w < 0 || w >= n {
+			panic("vertex out of range: " + strconv.Itoa(w))
+		}
+		if transpose {
+			h.edges[w] = append(h.edges[w], neighbor{v, c})
+		} else {
+			h.edges[v] = append(h.edges[v], neighbor{w, c})
+		}
+		return
+	}
+	for v = range h.edges {
+		g.Visit(v, do)
 		sort.Slice(h.edges[v], func(i, j int) bool {
 			if e := h.edges[v]; e[i].vertex == e[j].vertex {
 				return e[i].cost < e[j].cost
diff --git a/immutable_test.go b/immutable_test.go
index f530ab7..e2e9b5b 100644
--- a/immutable_test.go
+++ b/immutable_test.go
@@ -197,3 +197,29 @@ func TestDegreeImm(t *testing.T) {
 		t.Errorf("g5c.Degree(1) %s", mess)
 	}
 }
+
+func BenchmarkSort(b *testing.B) {
+	n := 1000
+	g := New(n)
+	for i := 0; i < 3*n; i++ {
+		g.Add(rand.Intn(n), rand.Intn(n))
+	}
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		_ = Sort(g)
+	}
+}
+
+func BenchmarkTranspose(b *testing.B) {
+	n := 1000
+	g := New(n)
+	for i := 0; i < 3*n; i++ {
+		g.Add(rand.Intn(n), rand.Intn(n))
+	}
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		_ = Transpose(g)
+	}
+}
diff --git a/mst.go b/mst.go
index dc72292..7a04f89 100644
--- a/mst.go
+++ b/mst.go
@@ -19,16 +19,18 @@ func MST(g Iterator) (parent []int) {
 
 	// Prim's algorithm
 	Q := newPrioQueue(cost)
+	var v int
+	do := func(w int, c int64) (skip bool) {
+		if Q.Contains(w) && c < cost[w] {
+			cost[w] = c
+			Q.Fix(w)
+			parent[w] = v
+		}
+		return
+	}
 	for Q.Len() > 0 {
-		v := Q.Pop()
-		g.Visit(v, func(w int, c int64) (skip bool) {
-			if Q.Contains(w) && c < cost[w] {
-				cost[w] = c
-				Q.Fix(w)
-				parent[w] = v
-			}
-			return
-		})
+		v = Q.Pop()
+		g.Visit(v, do)
 	}
 	return
 }
diff --git a/mst_test.go b/mst_test.go
index dff0c47..092b461 100644
--- a/mst_test.go
+++ b/mst_test.go
@@ -34,6 +34,7 @@ func TestMST(t *testing.T) {
 
 func BenchmarkMST(b *testing.B) {
 	n := 1000
+	b.ReportAllocs()
 	b.StopTimer()
 	g := New(n)
 	for i := 0; i < 2*n; i++ {
diff --git a/path.go b/path.go
index 850ddec..df86072 100644
--- a/path.go
+++ b/path.go
@@ -7,7 +7,7 @@ package graph
 // The time complexity is O((|E| + |V|)⋅log|V|), where |E| is the number of edges
 // and |V| the number of vertices in the graph.
 func ShortestPath(g Iterator, v, w int) (path []int, dist int64) {
-	parent, distances := ShortestPaths(g, v)
+	parent, distances := shortestPath(g, v, w)
 	path, dist = []int{}, distances[w]
 	if dist == -1 {
 		return
@@ -31,6 +31,12 @@ func ShortestPath(g Iterator, v, w int) (path []int, dist int64) {
 // The time complexity is O((|E| + |V|)⋅log|V|), where |E| is the number of edges
 // and |V| the number of vertices in the graph.
 func ShortestPaths(g Iterator, v int) (parent []int, dist []int64) {
+	// Use -1 to search for a vertex that doesn't exists so it will
+	// search for all the shortest paths from v.
+	return shortestPath(g, v, -1)
+}
+
+func shortestPath(g Iterator, v, w int) (parent []int, dist []int64) {
 	n := g.Order()
 	dist = make([]int64, n)
 	parent = make([]int, n)
@@ -42,23 +48,28 @@ func ShortestPaths(g Iterator, v int) (parent []int, dist []int64) {
 	// Dijkstra's algorithm
 	Q := emptyPrioQueue(dist)
 	Q.Push(v)
+
+	do := func(w int, d int64) (skip bool) {
+		if d < 0 {
+			return
+		}
+		alt := dist[v] + d
+		switch {
+		case dist[w] == -1:
+			dist[w], parent[w] = alt, v
+			Q.Push(w)
+		case alt < dist[w]:
+			dist[w], parent[w] = alt, v
+			Q.Fix(w)
+		}
+		return
+	}
 	for Q.Len() > 0 {
-		v := Q.Pop()
-		g.Visit(v, func(w int, d int64) (skip bool) {
-			if d < 0 {
-				return
-			}
-			alt := dist[v] + d
-			switch {
-			case dist[w] == -1:
-				dist[w], parent[w] = alt, v
-				Q.Push(w)
-			case alt < dist[w]:
-				dist[w], parent[w] = alt, v
-				Q.Fix(w)
-			}
+		v = Q.Pop()
+		if v == w {
 			return
-		})
+		}
+		g.Visit(v, do)
 	}
 	return
 }
diff --git a/path_test.go b/path_test.go
index 2350c8c..a3642f9 100644
--- a/path_test.go
+++ b/path_test.go
@@ -50,6 +50,21 @@ func TestShortestPath(t *testing.T) {
 	}
 }
 
+func BenchmarkShortestPath(b *testing.B) {
+	n := 1000
+	b.StopTimer()
+	g := New(n)
+	for i := 0; i < n; i++ {
+		g.Add(0, rand.Intn(n))
+		g.Add(rand.Intn(n), rand.Intn(n))
+	}
+	b.ReportAllocs()
+	b.StartTimer()
+	for i := 0; i < b.N; i++ {
+		_, _ = ShortestPath(g, 0, n-1)
+	}
+}
+
 func BenchmarkShortestPaths(b *testing.B) {
 	n := 1000
 	b.StopTimer()
@@ -58,6 +73,7 @@ func BenchmarkShortestPaths(b *testing.B) {
 		g.Add(0, rand.Intn(n))
 		g.Add(rand.Intn(n), rand.Intn(n))
 	}
+	b.ReportAllocs()
 	b.StartTimer()
 	for i := 0; i < b.N; i++ {
 		_, _ = ShortestPaths(g, 0)
diff --git a/testdata/bench_after/Acyclic b/testdata/bench_after/Acyclic
new file mode 100644
index 0000000..4681931
--- /dev/null
+++ b/testdata/bench_after/Acyclic
@@ -0,0 +1,7 @@
+goos: linux
+goarch: amd64
+pkg: github.com/rschio/graph
+cpu: Intel(R) Core(TM) i5-8350U CPU @ 1.70GHz
+BenchmarkAcyclic-8   	   16905	     66498 ns/op	   12386 B/op	      13 allocs/op
+PASS
+ok  	github.com/rschio/graph	1.848s
diff --git a/testdata/bench_after/BFS b/testdata/bench_after/BFS
new file mode 100644
index 0000000..4d9cdb8
--- /dev/null
+++ b/testdata/bench_after/BFS
@@ -0,0 +1,7 @@
+goos: linux
+goarch: amd64
+pkg: github.com/rschio/graph
+cpu: Intel(R) Core(TM) i5-8350U CPU @ 1.70GHz
+BenchmarkBFS-8   	    5128	    206326 ns/op	   23213 B/op	      17 allocs/op
+PASS
+ok  	github.com/rschio/graph	1.089s
diff --git a/testdata/bench_after/Bipartition b/testdata/bench_after/Bipartition
new file mode 100644
index 0000000..72dd884
--- /dev/null
+++ b/testdata/bench_after/Bipartition
@@ -0,0 +1,7 @@
+goos: linux
+goarch: amd64
+pkg: github.com/rschio/graph
+cpu: Intel(R) Core(TM) i5-8350U CPU @ 1.70GHz
+BenchmarkBipartition-8   	 2384719	      1398 ns/op	    2792 B/op	      14 allocs/op
+PASS
+ok  	github.com/rschio/graph	3.860s
diff --git a/testdata/bench_after/Components b/testdata/bench_after/Components
new file mode 100644
index 0000000..41b1268
--- /dev/null
+++ b/testdata/bench_after/Components
@@ -0,0 +1,7 @@
+goos: linux
+goarch: amd64
+pkg: github.com/rschio/graph
+cpu: Intel(R) Core(TM) i5-8350U CPU @ 1.70GHz
+BenchmarkComponents-8   	    7056	    148831 ns/op	   54846 B/op	     235 allocs/op
+PASS
+ok  	github.com/rschio/graph	1.072s
diff --git a/testdata/bench_after/Connected b/testdata/bench_after/Connected
new file mode 100644
index 0000000..b247c3c
--- /dev/null
+++ b/testdata/bench_after/Connected
@@ -0,0 +1,7 @@
+goos: linux
+goarch: amd64
+pkg: github.com/rschio/graph
+cpu: Intel(R) Core(TM) i5-8350U CPU @ 1.70GHz
+BenchmarkConnected-8   	   11476	    103912 ns/op	    8267 B/op	       5 allocs/op
+PASS
+ok  	github.com/rschio/graph	1.986s
diff --git a/testdata/bench_after/EulerDirected b/testdata/bench_after/EulerDirected
new file mode 100644
index 0000000..613ae4e
--- /dev/null
+++ b/testdata/bench_after/EulerDirected
@@ -0,0 +1,7 @@
+goos: linux
+goarch: amd64
+pkg: github.com/rschio/graph
+cpu: Intel(R) Core(TM) i5-8350U CPU @ 1.70GHz
+BenchmarkEulerDirected-8   	  589666	      2005 ns/op	     960 B/op	       4 allocs/op
+PASS
+ok  	github.com/rschio/graph	2.041s
diff --git a/testdata/bench_after/EulerUndirected b/testdata/bench_after/EulerUndirected
new file mode 100644
index 0000000..1c55a66
--- /dev/null
+++ b/testdata/bench_after/EulerUndirected
@@ -0,0 +1,7 @@
+goos: linux
+goarch: amd64
+pkg: github.com/rschio/graph
+cpu: Intel(R) Core(TM) i5-8350U CPU @ 1.70GHz
+BenchmarkEulerUndirected-8   	  508767	      2387 ns/op	     968 B/op	       5 allocs/op
+PASS
+ok  	github.com/rschio/graph	2.188s
diff --git a/testdata/bench_after/MST b/testdata/bench_after/MST
new file mode 100644
index 0000000..52f14dc
--- /dev/null
+++ b/testdata/bench_after/MST
@@ -0,0 +1,7 @@
+goos: linux
+goarch: amd64
+pkg: github.com/rschio/graph
+cpu: Intel(R) Core(TM) i5-8350U CPU @ 1.70GHz
+BenchmarkMST-8   	    5379	    189717 ns/op	   32951 B/op	       8 allocs/op
+PASS
+ok  	github.com/rschio/graph	1.048s
diff --git a/testdata/bench_after/ShortestPath b/testdata/bench_after/ShortestPath
new file mode 100644
index 0000000..63b0cc1
--- /dev/null
+++ b/testdata/bench_after/ShortestPath
@@ -0,0 +1,7 @@
+goos: linux
+goarch: amd64
+pkg: github.com/rschio/graph
+cpu: Intel(R) Core(TM) i5-8350U CPU @ 1.70GHz
+BenchmarkShortestPath-8   	   26695	     60170 ns/op	   39753 B/op	      21 allocs/op
+PASS
+ok  	github.com/rschio/graph	3.108s
diff --git a/testdata/bench_after/ShortestPaths b/testdata/bench_after/ShortestPaths
new file mode 100644
index 0000000..8c6f9c9
--- /dev/null
+++ b/testdata/bench_after/ShortestPaths
@@ -0,0 +1,7 @@
+goos: linux
+goarch: amd64
+pkg: github.com/rschio/graph
+cpu: Intel(R) Core(TM) i5-8350U CPU @ 1.70GHz
+BenchmarkShortestPaths-8   	   14500	     79967 ns/op	   39729 B/op	      19 allocs/op
+PASS
+ok  	github.com/rschio/graph	2.003s
diff --git a/testdata/bench_after/Sort b/testdata/bench_after/Sort
new file mode 100644
index 0000000..fb298dd
--- /dev/null
+++ b/testdata/bench_after/Sort
@@ -0,0 +1,7 @@
+goos: linux
+goarch: amd64
+pkg: github.com/rschio/graph
+cpu: Intel(R) Core(TM) i5-8350U CPU @ 1.70GHz
+BenchmarkSort-8   	    2433	    499979 ns/op	  201219 B/op	    5031 allocs/op
+PASS
+ok  	github.com/rschio/graph	1.272s
diff --git a/testdata/bench_after/TopSort b/testdata/bench_after/TopSort
new file mode 100644
index 0000000..5edc163
--- /dev/null
+++ b/testdata/bench_after/TopSort
@@ -0,0 +1,7 @@
+goos: linux
+goarch: amd64
+pkg: github.com/rschio/graph
+cpu: Intel(R) Core(TM) i5-8350U CPU @ 1.70GHz
+BenchmarkTopSort-8   	   17028	     69394 ns/op	   16474 B/op	      22 allocs/op
+PASS
+ok  	github.com/rschio/graph	1.900s
diff --git a/testdata/bench_after/Transpose b/testdata/bench_after/Transpose
new file mode 100644
index 0000000..3b2db5e
--- /dev/null
+++ b/testdata/bench_after/Transpose
@@ -0,0 +1,7 @@
+goos: linux
+goarch: amd64
+pkg: github.com/rschio/graph
+cpu: Intel(R) Core(TM) i5-8350U CPU @ 1.70GHz
+BenchmarkTranspose-8   	    3045	    401361 ns/op	  169624 B/op	    4002 allocs/op
+PASS
+ok  	github.com/rschio/graph	1.267s
diff --git a/testdata/bench_before/Acyclic b/testdata/bench_before/Acyclic
new file mode 100644
index 0000000..27afc9b
--- /dev/null
+++ b/testdata/bench_before/Acyclic
@@ -0,0 +1,7 @@
+goos: linux
+goarch: amd64
+pkg: github.com/rschio/graph
+cpu: Intel(R) Core(TM) i5-8350U CPU @ 1.70GHz
+BenchmarkAcyclic-8   	    9379	    127766 ns/op	   51988 B/op	    1171 allocs/op
+PASS
+ok  	github.com/rschio/graph	2.072s
diff --git a/testdata/bench_before/BFS b/testdata/bench_before/BFS
new file mode 100644
index 0000000..469edd6
--- /dev/null
+++ b/testdata/bench_before/BFS
@@ -0,0 +1,7 @@
+goos: linux
+goarch: amd64
+pkg: github.com/rschio/graph
+cpu: Intel(R) Core(TM) i5-8350U CPU @ 1.70GHz
+BenchmarkBFS-8   	    3776	    269224 ns/op	   86849 B/op	    1015 allocs/op
+PASS
+ok  	github.com/rschio/graph	1.057s
diff --git a/testdata/bench_before/Bipartition b/testdata/bench_before/Bipartition
new file mode 100644
index 0000000..142510f
--- /dev/null
+++ b/testdata/bench_before/Bipartition
@@ -0,0 +1,7 @@
+goos: linux
+goarch: amd64
+pkg: github.com/rschio/graph
+cpu: Intel(R) Core(TM) i5-8350U CPU @ 1.70GHz
+BenchmarkBipartition-8   	 2253801	      1875 ns/op	    3616 B/op	      26 allocs/op
+PASS
+ok  	github.com/rschio/graph	4.708s
diff --git a/testdata/bench_before/Components b/testdata/bench_before/Components
new file mode 100644
index 0000000..15719cf
--- /dev/null
+++ b/testdata/bench_before/Components
@@ -0,0 +1,7 @@
+goos: linux
+goarch: amd64
+pkg: github.com/rschio/graph
+cpu: Intel(R) Core(TM) i5-8350U CPU @ 1.70GHz
+BenchmarkComponents-8   	    5728	    195865 ns/op	   86816 B/op	    1234 allocs/op
+PASS
+ok  	github.com/rschio/graph	1.148s
diff --git a/testdata/bench_before/Connected b/testdata/bench_before/Connected
new file mode 100644
index 0000000..89109a9
--- /dev/null
+++ b/testdata/bench_before/Connected
@@ -0,0 +1,7 @@
+goos: linux
+goarch: amd64
+pkg: github.com/rschio/graph
+cpu: Intel(R) Core(TM) i5-8350U CPU @ 1.70GHz
+BenchmarkConnected-8   	    7894	    151161 ns/op	   40237 B/op	    1004 allocs/op
+PASS
+ok  	github.com/rschio/graph	2.047s
diff --git a/testdata/bench_before/EulerDirected b/testdata/bench_before/EulerDirected
new file mode 100644
index 0000000..8b1c551
--- /dev/null
+++ b/testdata/bench_before/EulerDirected
@@ -0,0 +1,7 @@
+goos: linux
+goarch: amd64
+pkg: github.com/rschio/graph
+cpu: Intel(R) Core(TM) i5-8350U CPU @ 1.70GHz
+BenchmarkEulerDirected-8   	  147134	      7276 ns/op	    5712 B/op	     103 allocs/op
+PASS
+ok  	github.com/rschio/graph	1.159s
diff --git a/testdata/bench_before/EulerUndirected b/testdata/bench_before/EulerUndirected
new file mode 100644
index 0000000..490999f
--- /dev/null
+++ b/testdata/bench_before/EulerUndirected
@@ -0,0 +1,7 @@
+goos: linux
+goarch: amd64
+pkg: github.com/rschio/graph
+cpu: Intel(R) Core(TM) i5-8350U CPU @ 1.70GHz
+BenchmarkEulerUndirected-8   	  152704	      7065 ns/op	    5720 B/op	     104 allocs/op
+PASS
+ok  	github.com/rschio/graph	1.164s
diff --git a/testdata/bench_before/MST b/testdata/bench_before/MST
new file mode 100644
index 0000000..f261fba
--- /dev/null
+++ b/testdata/bench_before/MST
@@ -0,0 +1,7 @@
+goos: linux
+goarch: amd64
+pkg: github.com/rschio/graph
+cpu: Intel(R) Core(TM) i5-8350U CPU @ 1.70GHz
+BenchmarkMST-8   	    4191	    249128 ns/op	   96883 B/op	    1006 allocs/op
+PASS
+ok  	github.com/rschio/graph	1.078s
diff --git a/testdata/bench_before/ShortestPath b/testdata/bench_before/ShortestPath
new file mode 100644
index 0000000..f63c789
--- /dev/null
+++ b/testdata/bench_before/ShortestPath
@@ -0,0 +1,7 @@
+goos: linux
+goarch: amd64
+pkg: github.com/rschio/graph
+cpu: Intel(R) Core(TM) i5-8350U CPU @ 1.70GHz
+BenchmarkShortestPath-8   	    8378	    140683 ns/op	   79875 B/op	     856 allocs/op
+PASS
+ok  	github.com/rschio/graph	1.198s
diff --git a/testdata/bench_before/ShortestPaths b/testdata/bench_before/ShortestPaths
new file mode 100644
index 0000000..b578115
--- /dev/null
+++ b/testdata/bench_before/ShortestPaths
@@ -0,0 +1,7 @@
+goos: linux
+goarch: amd64
+pkg: github.com/rschio/graph
+cpu: Intel(R) Core(TM) i5-8350U CPU @ 1.70GHz
+BenchmarkShortestPaths-8   	   10394	    121272 ns/op	   79226 B/op	     841 allocs/op
+PASS
+ok  	github.com/rschio/graph	2.118s
diff --git a/testdata/bench_before/Sort b/testdata/bench_before/Sort
new file mode 100644
index 0000000..117ff1f
--- /dev/null
+++ b/testdata/bench_before/Sort
@@ -0,0 +1,7 @@
+goos: linux
+goarch: amd64
+pkg: github.com/rschio/graph
+cpu: Intel(R) Core(TM) i5-8350U CPU @ 1.70GHz
+BenchmarkSort-8   	    2175	    608159 ns/op	  249174 B/op	    6030 allocs/op
+PASS
+ok  	github.com/rschio/graph	1.383s
diff --git a/testdata/bench_before/TopSort b/testdata/bench_before/TopSort
new file mode 100644
index 0000000..2126721
--- /dev/null
+++ b/testdata/bench_before/TopSort
@@ -0,0 +1,7 @@
+goos: linux
+goarch: amd64
+pkg: github.com/rschio/graph
+cpu: Intel(R) Core(TM) i5-8350U CPU @ 1.70GHz
+BenchmarkTopSort-8   	    9980	    134713 ns/op	   56076 B/op	    1180 allocs/op
+PASS
+ok  	github.com/rschio/graph	2.332s
diff --git a/testdata/bench_before/Transpose b/testdata/bench_before/Transpose
new file mode 100644
index 0000000..95e07c0
--- /dev/null
+++ b/testdata/bench_before/Transpose
@@ -0,0 +1,7 @@
+goos: linux
+goarch: amd64
+pkg: github.com/rschio/graph
+cpu: Intel(R) Core(TM) i5-8350U CPU @ 1.70GHz
+BenchmarkTranspose-8   	    2698	    404269 ns/op	  217577 B/op	    5001 allocs/op
+PASS
+ok  	github.com/rschio/graph	1.140s
diff --git a/testdata/bench_results/Acyclic b/testdata/bench_results/Acyclic
new file mode 100644
index 0000000..f057162
--- /dev/null
+++ b/testdata/bench_results/Acyclic
@@ -0,0 +1,8 @@
+name       old time/op    new time/op    delta
+Acyclic-8     128µs ± 0%      66µs ± 0%  -47.95%
+
+name       old alloc/op   new alloc/op   delta
+Acyclic-8    52.0kB ± 0%    12.4kB ± 0%  -76.18%
+
+name       old allocs/op  new allocs/op  delta
+Acyclic-8     1.17k ± 0%     0.01k ± 0%  -98.89%
diff --git a/testdata/bench_results/BFS b/testdata/bench_results/BFS
new file mode 100644
index 0000000..357c0ca
--- /dev/null
+++ b/testdata/bench_results/BFS
@@ -0,0 +1,8 @@
+name   old time/op    new time/op    delta
+BFS-8     269µs ± 0%     206µs ± 0%  -23.36%
+
+name   old alloc/op   new alloc/op   delta
+BFS-8    86.8kB ± 0%    23.2kB ± 0%  -73.27%
+
+name   old allocs/op  new allocs/op  delta
+BFS-8     1.01k ± 0%     0.02k ± 0%  -98.33%
diff --git a/testdata/bench_results/Bipartition b/testdata/bench_results/Bipartition
new file mode 100644
index 0000000..f8a3cab
--- /dev/null
+++ b/testdata/bench_results/Bipartition
@@ -0,0 +1,8 @@
+name           old time/op    new time/op    delta
+Bipartition-8    1.88µs ± 0%    1.40µs ± 0%  -25.44%
+
+name           old alloc/op   new alloc/op   delta
+Bipartition-8    3.62kB ± 0%    2.79kB ± 0%  -22.79%
+
+name           old allocs/op  new allocs/op  delta
+Bipartition-8      26.0 ± 0%      14.0 ± 0%  -46.15%
diff --git a/testdata/bench_results/Components b/testdata/bench_results/Components
new file mode 100644
index 0000000..f9d7a86
--- /dev/null
+++ b/testdata/bench_results/Components
@@ -0,0 +1,8 @@
+name          old time/op    new time/op    delta
+Components-8     196µs ± 0%     149µs ± 0%  -24.01%
+
+name          old alloc/op   new alloc/op   delta
+Components-8    86.8kB ± 0%    54.8kB ± 0%  -36.83%
+
+name          old allocs/op  new allocs/op  delta
+Components-8     1.23k ± 0%     0.23k ± 0%  -80.96%
diff --git a/testdata/bench_results/Connected b/testdata/bench_results/Connected
new file mode 100644
index 0000000..adc21e3
--- /dev/null
+++ b/testdata/bench_results/Connected
@@ -0,0 +1,8 @@
+name         old time/op    new time/op    delta
+Connected-8     151µs ± 0%     104µs ± 0%  -31.26%
+
+name         old alloc/op   new alloc/op   delta
+Connected-8    40.2kB ± 0%     8.3kB ± 0%  -79.45%
+
+name         old allocs/op  new allocs/op  delta
+Connected-8     1.00k ± 0%     0.01k ± 0%  -99.50%
diff --git a/testdata/bench_results/EulerDirected b/testdata/bench_results/EulerDirected
new file mode 100644
index 0000000..0ef476c
--- /dev/null
+++ b/testdata/bench_results/EulerDirected
@@ -0,0 +1,8 @@
+name             old time/op    new time/op    delta
+EulerDirected-8    7.28µs ± 0%    2.00µs ± 0%  -72.44%
+
+name             old alloc/op   new alloc/op   delta
+EulerDirected-8    5.71kB ± 0%    0.96kB ± 0%  -83.19%
+
+name             old allocs/op  new allocs/op  delta
+EulerDirected-8       103 ± 0%         4 ± 0%  -96.12%
diff --git a/testdata/bench_results/EulerUndirected b/testdata/bench_results/EulerUndirected
new file mode 100644
index 0000000..c750c1c
--- /dev/null
+++ b/testdata/bench_results/EulerUndirected
@@ -0,0 +1,8 @@
+name               old time/op    new time/op    delta
+EulerUndirected-8    7.07µs ± 0%    2.39µs ± 0%  -66.21%
+
+name               old alloc/op   new alloc/op   delta
+EulerUndirected-8    5.72kB ± 0%    0.97kB ± 0%  -83.08%
+
+name               old allocs/op  new allocs/op  delta
+EulerUndirected-8       104 ± 0%         5 ± 0%  -95.19%
diff --git a/testdata/bench_results/MST b/testdata/bench_results/MST
new file mode 100644
index 0000000..d3c706b
--- /dev/null
+++ b/testdata/bench_results/MST
@@ -0,0 +1,8 @@
+name   old time/op    new time/op    delta
+MST-8     249µs ± 0%     190µs ± 0%  -23.85%
+
+name   old alloc/op   new alloc/op   delta
+MST-8    96.9kB ± 0%    33.0kB ± 0%  -65.99%
+
+name   old allocs/op  new allocs/op  delta
+MST-8     1.01k ± 0%     0.01k ± 0%  -99.20%
diff --git a/testdata/bench_results/ShortestPath b/testdata/bench_results/ShortestPath
new file mode 100644
index 0000000..94d9b58
--- /dev/null
+++ b/testdata/bench_results/ShortestPath
@@ -0,0 +1,8 @@
+name            old time/op    new time/op    delta
+ShortestPath-8     141µs ± 0%      60µs ± 0%  -57.23%
+
+name            old alloc/op   new alloc/op   delta
+ShortestPath-8    79.9kB ± 0%    39.8kB ± 0%  -50.23%
+
+name            old allocs/op  new allocs/op  delta
+ShortestPath-8       856 ± 0%        21 ± 0%  -97.55%
diff --git a/testdata/bench_results/ShortestPaths b/testdata/bench_results/ShortestPaths
new file mode 100644
index 0000000..9407000
--- /dev/null
+++ b/testdata/bench_results/ShortestPaths
@@ -0,0 +1,8 @@
+name             old time/op    new time/op    delta
+ShortestPaths-8     121µs ± 0%      80µs ± 0%  -34.06%
+
+name             old alloc/op   new alloc/op   delta
+ShortestPaths-8    79.2kB ± 0%    39.7kB ± 0%  -49.85%
+
+name             old allocs/op  new allocs/op  delta
+ShortestPaths-8       841 ± 0%        19 ± 0%  -97.74%
diff --git a/testdata/bench_results/Sort b/testdata/bench_results/Sort
new file mode 100644
index 0000000..c71f8f9
--- /dev/null
+++ b/testdata/bench_results/Sort
@@ -0,0 +1,8 @@
+name    old time/op    new time/op    delta
+Sort-8     608µs ± 0%     500µs ± 0%  -17.79%
+
+name    old alloc/op   new alloc/op   delta
+Sort-8     249kB ± 0%     201kB ± 0%  -19.25%
+
+name    old allocs/op  new allocs/op  delta
+Sort-8     6.03k ± 0%     5.03k ± 0%  -16.57%
diff --git a/testdata/bench_results/TopSort b/testdata/bench_results/TopSort
new file mode 100644
index 0000000..0f97727
--- /dev/null
+++ b/testdata/bench_results/TopSort
@@ -0,0 +1,8 @@
+name       old time/op    new time/op    delta
+TopSort-8     135µs ± 0%      69µs ± 0%  -48.49%
+
+name       old alloc/op   new alloc/op   delta
+TopSort-8    56.1kB ± 0%    16.5kB ± 0%  -70.62%
+
+name       old allocs/op  new allocs/op  delta
+TopSort-8     1.18k ± 0%     0.02k ± 0%  -98.14%
diff --git a/testdata/bench_results/Transpose b/testdata/bench_results/Transpose
new file mode 100644
index 0000000..85583fc
--- /dev/null
+++ b/testdata/bench_results/Transpose
@@ -0,0 +1,8 @@
+name         old time/op    new time/op    delta
+Transpose-8     404µs ± 0%     401µs ± 0%   -0.72%
+
+name         old alloc/op   new alloc/op   delta
+Transpose-8     218kB ± 0%     170kB ± 0%  -22.04%
+
+name         old allocs/op  new allocs/op  delta
+Transpose-8     5.00k ± 0%     4.00k ± 0%  -19.98%
diff --git a/testdata/benchdiff.sh b/testdata/benchdiff.sh
new file mode 100755
index 0000000..4b9914f
--- /dev/null
+++ b/testdata/benchdiff.sh
@@ -0,0 +1,2 @@
+#!/bin/sh
+benchstat -delta-test none testdata/bench_before/${1} testdata/bench_after/${1} | tee testdata/bench_results/${1}
diff --git a/top.go b/top.go
index e03d97f..dc85611 100644
--- a/top.go
+++ b/top.go
@@ -19,11 +19,12 @@ func Acyclic(g Iterator) bool {
 // Kahn's algorithm
 func topsort(g Iterator, output bool) (order []int, acyclic bool) {
 	indegree := make([]int, g.Order())
+	addIndegree := func(w int, _ int64) (skip bool) {
+		indegree[w]++
+		return
+	}
 	for v := range indegree {
-		g.Visit(v, func(w int, _ int64) (skip bool) {
-			indegree[w]++
-			return
-		})
+		g.Visit(v, addIndegree)
 	}
 
 	// Invariant: this queue holds all vertices with indegree 0.
@@ -34,6 +35,13 @@ func topsort(g Iterator, output bool) (order []int, acyclic bool) {
 		}
 	}
 
+	subIndegree := func(w int, _ int64) (skip bool) {
+		indegree[w]--
+		if indegree[w] == 0 {
+			queue = append(queue, w)
+		}
+		return
+	}
 	order = []int{}
 	vertexCount := 0
 	for len(queue) > 0 {
@@ -43,13 +51,7 @@ func topsort(g Iterator, output bool) (order []int, acyclic bool) {
 			order = append(order, v)
 		}
 		vertexCount++
-		g.Visit(v, func(w int, _ int64) (skip bool) {
-			indegree[w]--
-			if indegree[w] == 0 {
-				queue = append(queue, w)
-			}
-			return
-		})
+		g.Visit(v, subIndegree)
 	}
 	if vertexCount != g.Order() {
 		return
diff --git a/top_test.go b/top_test.go
index 319c0ee..c042165 100644
--- a/top_test.go
+++ b/top_test.go
@@ -84,6 +84,7 @@ func TestAcyclic(t *testing.T) {
 
 func BenchmarkAcyclic(b *testing.B) {
 	n := 1000
+	b.ReportAllocs()
 	b.StopTimer()
 	g := New(n)
 	for i := 0; i < 2*n; i++ {
@@ -100,6 +101,7 @@ func BenchmarkAcyclic(b *testing.B) {
 
 func BenchmarkTopSort(b *testing.B) {
 	n := 1000
+	b.ReportAllocs()
 	b.StopTimer()
 	g := New(n)
 	for i := 0; i < 2*n; i++ {
diff --git a/weak.go b/weak.go
index c07f033..43ffeb1 100644
--- a/weak.go
+++ b/weak.go
@@ -29,18 +29,21 @@ func Components(g Iterator) [][]int {
 func components(g Iterator) (sets disjointSets, count int) {
 	n := g.Order()
 	sets, count = makeSingletons(n), n
-	for v := 0; v < n && count > 1; v++ {
-		g.Visit(v, func(w int, _ int64) (skip bool) {
-			x, y := sets.find(v), sets.find(w)
-			if x != y {
-				sets.union(x, y)
-				count--
-				if count == 1 {
-					skip = true
-				}
+
+	var v int
+	do := func(w int, _ int64) (skip bool) {
+		x, y := sets.find(v), sets.find(w)
+		if x != y {
+			sets.union(x, y)
+			count--
+			if count == 1 {
+				skip = true
 			}
-			return
-		})
+		}
+		return
+	}
+	for v = 0; v < n && count > 1; v++ {
+		g.Visit(v, do)
 	}
 	return
 }
diff --git a/weak_test.go b/weak_test.go
index 581a834..95fb78b 100644
--- a/weak_test.go
+++ b/weak_test.go
@@ -54,6 +54,7 @@ func TestComponents(t *testing.T) {
 
 func BenchmarkConnected(b *testing.B) {
 	n := 1000
+	b.ReportAllocs()
 	b.StopTimer()
 	g := New(n)
 	for i := 0; i < n; i++ {
@@ -67,6 +68,7 @@ func BenchmarkConnected(b *testing.B) {
 
 func BenchmarkComponents(b *testing.B) {
 	n := 1000
+	b.ReportAllocs()
 	b.StopTimer()
 	g := New(n)
 	for i := 0; i < n; i++ {