Merge da08a10525 into 14f714261f

graphs/graph.go

@@ -0,0 +1,119 @@
+package graphs
+
+// Graph holds vertices and edges of a graph
+type Graph struct {
+	isDirected bool
+	vertices   []node
+}
+
+type node struct {
+	name  interface{}
+	edges []interface{}
+}
+
+const infinity = int(^uint(0) >> 1)
+
+// NewDirectedGraph is for creating a directed graph
+func NewDirectedGraph() *Graph {
+	g := Graph{}
+	g.vertices = make([]node, 0)
+	g.isDirected = true
+	return &g
+}
+
+// NewUndirectedGraph is for creating an undirected graph
+func NewUndirectedGraph() *Graph {
+	g := Graph{}
+	g.vertices = make([]node, 0)
+	g.isDirected = false
+	return &g
+}
+
+// AddVertice is for adding a new vertice. id vertice exists do nothing
+func (g *Graph) AddVertice(name interface{}) {
+	g.addVertice(name)
+}
+
+// AddEdge if for adding a new edge.
+func (g *Graph) AddEdge(from, to interface{}) {
+	g.addEdge(from, to)
+}
+
+// GetEdge is for getting all the edges of vertice n
+func (g *Graph) GetEdge(n interface{}) []interface{} {
+	return g.getEdge(n)
+}
+
+// GetVertices is for getting all vertices info
+func (g *Graph) GetVertices() []interface{} {
+	return g.getVertices()
+}
+
+// ShortestPath is for finding shortest path from edge s to t by using belman-ford algorithm
+func (g *Graph) ShortestPath(s, t interface{}) map[interface{}]int {
+	return g.shortestPath(s, t)
+}
+
+func (g *Graph) addVertice(name interface{}) int {
+	for i, v := range g.vertices {
+		if v.name == name {
+			return i
+		}
+	}
+	n := node{}
+	n.name = name
+	n.edges = make([]interface{}, 0)
+	g.vertices = append(g.vertices, n)
+
+	return len(g.vertices) - 1
+}
+
+func (g *Graph) addEdge(from, to interface{}) {
+	f := g.addVertice(from)
+	t := g.addVertice(to)
+	g.vertices[f].edges = append(g.vertices[f].edges, to)
+	if !g.isDirected {
+		g.vertices[t].edges = append(g.vertices[t].edges, from)
+	}
+}
+
+func (g *Graph) getEdge(n interface{}) []interface{} {
+	for _, v := range g.vertices {
+		if v.name == n {
+			return v.edges
+		}
+	}
+	// todo throw exception
+	return nil
+}
+
+func (g *Graph) getVertices() []interface{} {
+	vertices := make([]interface{}, 0)
+	for i := 0; i < len(g.vertices); i++ {
+		vertices = append(vertices, g.vertices[i].name)
+	}
+	return vertices
+}
+
+func (g *Graph) shortestPath(sName, tName interface{}) map[interface{}]int {
+	n := len(g.vertices)
+	s := g.addVertice(sName)
+	dist := make([]int, n)
+	for i := 0; i < n; i++ {
+		dist[i] = infinity
+	}
+	dist[s] = 0
+	for u := 0; u < n-1; u++ {
+		for _, vName := range g.vertices[u].edges {
+			v := g.addVertice(vName)
+			if dist[u] != infinity && dist[u]+1 < dist[v] {
+				dist[v] = dist[u] + 1
+			}
+		}
+	}
+	result := make(map[interface{}]int)
+	for i, d := range dist {
+		result[g.vertices[i].name] = d
+	}
+	return result
+}

graphs/graph_test.go

@@ -0,0 +1,102 @@
+package graphs
+
+import (
+	"testing"
+)
+
+func TestGrsphAddVertice(t *testing.T) {
+	g1 := NewDirectedGraph()
+	g1.AddVertice("a")
+	g1.AddVertice("b")
+	g1.AddVertice("c")
+	g1.AddVertice("d")
+	actualValue1 := g1.GetVertices()
+	expectedValue1 := []string{"a", "b", "c", "d"}
+	for i, v := range expectedValue1 {
+		if v != actualValue1[i] {
+			t.Errorf("Got %v expected %v", actualValue1, expectedValue1)
+			return
+		}
+	}
+
+	g2 := NewDirectedGraph()
+	g2.AddVertice(1)
+	g2.AddVertice(2)
+	g2.AddVertice(3)
+	g2.AddVertice(4)
+	actualValue2 := g2.GetVertices()
+
+	expectedValue2 := []int{1, 2, 3, 4}
+	for i, v := range expectedValue2 {
+		if v != actualValue2[i] {
+			t.Errorf("Got %v expected %v", actualValue2, expectedValue2)
+			return
+		}
+	}
+
+	g3 := NewUndirectedGraph()
+	g3.AddVertice("a")
+	g3.AddVertice("b")
+	g3.AddVertice("c")
+	g3.AddVertice("d")
+	actualValue3 := g3.GetVertices()
+	expectedValue3 := []string{"a", "b", "c", "d"}
+	for i, v := range expectedValue3 {
+		if v != actualValue3[i] {
+			t.Errorf("Got %v expected %v", actualValue3, expectedValue3)
+			return
+		}
+	}
+}
+
+func TestGrsphAddEdge(t *testing.T) {
+	g1 := NewDirectedGraph()
+	g1.AddVertice("a")
+	g1.AddVertice("b")
+	g1.AddEdge("a", "b")
+	g1.AddEdge("c", "a")
+	actualValue1 := g1.GetEdge("a")
+	expectedValue1 := []string{"b"}
+	for i, v := range expectedValue1 {
+		if v != actualValue1[i] {
+			t.Errorf("Got %v expected %v", actualValue1, expectedValue1)
+			return
+		}
+	}
+
+	g2 := NewUndirectedGraph()
+	g2.AddVertice("a")
+	g2.AddVertice("b")
+	g2.AddEdge("a", "b")
+	g2.AddEdge("c", "a")
+	actualValue2 := g2.GetEdge("a")
+	expectedValue2 := []string{"b", "c"}
+	for i, v := range expectedValue2 {
+		if v != actualValue2[i] {
+			t.Errorf("Got %v expected %v", actualValue2, expectedValue2)
+			return
+		}
+	}
+}
+
+func TestShortestPath(t *testing.T) {
+	g := NewDirectedGraph()
+	g.addEdge("a", "b")
+	g.addEdge("b", "c")
+	g.addEdge("c", "a")
+	g.addEdge("c", "d")
+
+	tests := [][]interface{}{
+		{1, "a", 0},
+		{2, "b", 1},
+		{3, "c", 2},
+		{4, "d", 3},
+	}
+
+	for _, test := range tests {
+		actualValue, expectedValue := g.shortestPath("a", "b")[test[1]], test[2]
+		if actualValue != expectedValue {
+			t.Errorf("Got %v expected %v", actualValue, expectedValue)
+		}
+	}
+}