From aa48432371e69091a012bd7f60237ca1af642f72 Mon Sep 17 00:00:00 2001
From: DavidCai <davidcai1993@yahoo.com>
Date: Sun, 1 Jan 2017 14:24:01 +0800
Subject: [PATCH] implement basic undirected graph

---
 .travis.yml         |  5 ++--
 Makefile            |  5 ++--
 graph/graph.go      | 66 +++++++++++++++++++++++++++++++++++++++++++++
 graph/graph_test.go | 47 ++++++++++++++++++++++++++++++++
 4 files changed, 119 insertions(+), 4 deletions(-)
 create mode 100644 graph/graph.go
 create mode 100644 graph/graph_test.go

diff --git a/.travis.yml b/.travis.yml
index 0f46aa8..7a15156 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -13,7 +13,8 @@ script:
   - go test -v -race -coverprofile=mh.coverprofile ./min-heap
   - go test -v -race -coverprofile=avl.coverprofile ./avl-tree
   - go test -v -race -coverprofile=pat.coverprofile ./pat-tree
-  - go test -v -race -coverprofile=pat.coverprofile ./sort
-  - go test -v -race -coverprofile=pat.coverprofile ./search
+  - go test -v -race -coverprofile=sort.coverprofile ./sort
+  - go test -v -race -coverprofile=search.coverprofile ./search
+  - go test -v -race -coverprofile=graph.coverprofile ./graph
   - gover
   - goveralls -coverprofile=gover.coverprofile -service=travis-ci
\ No newline at end of file
diff --git a/Makefile b/Makefile
index b9e2e52..2e73f46 100644
--- a/Makefile
+++ b/Makefile
@@ -9,8 +9,9 @@ cover:
 	go test -v -race -coverprofile=bt.coverprofile ./b-tree
 	go test -v -race -coverprofile=avl.coverprofile ./avl-tree
 	go test -v -race -coverprofile=pat.coverprofile ./pat-tree
-	go test -v -race -coverprofile=pat.coverprofile ./sort
-	go test -v -race -coverprofile=pat.coverprofile ./search
+	go test -v -race -coverprofile=sort.coverprofile ./sort
+	go test -v -race -coverprofile=search.coverprofile ./search
+	go test -v -race -coverprofile=graph.coverprofile ./graph
 	gover
 	go tool cover -html=gover.coverprofile
 	rm -rf *.coverprofile
diff --git a/graph/graph.go b/graph/graph.go
new file mode 100644
index 0000000..61f78b7
--- /dev/null
+++ b/graph/graph.go
@@ -0,0 +1,66 @@
+package graph
+
+import (
+	"fmt"
+)
+
+const errInvaliVertexNumber = "graph: invalid vertex number %v"
+
+// Graph represents an undirected graph.
+type Graph struct {
+	bags  [][]int
+	edges int
+}
+
+// New returns a new undirected graph instance with v vertexs.
+func New(v int) *Graph {
+	return &Graph{bags: make([][]int, v)}
+}
+
+// Vertexs returns the number of vertexs of the graph.
+func (g Graph) Vertexs() int {
+	return len(g.bags)
+}
+
+// Edges returns the number of edges of the graph.
+func (g Graph) Edges() int {
+	return g.edges
+}
+
+// addEdge adds an edge to the graph.
+func (g *Graph) addEdge(v, w int) {
+	if v < 0 || v >= len(g.bags) {
+		panic(fmt.Errorf(errInvaliVertexNumber, v))
+	}
+
+	if w < 0 || w >= len(g.bags) {
+		panic(fmt.Errorf(errInvaliVertexNumber, w))
+	}
+
+	for _, b := range g.bags[v] {
+		if b == w {
+			panic(fmt.Errorf(errInvaliVertexNumber, w))
+		}
+	}
+
+	g.bags[v] = append(g.bags[v], w)
+
+	for _, b := range g.bags[w] {
+		if b == v {
+			panic(fmt.Errorf(errInvaliVertexNumber, v))
+		}
+	}
+
+	g.bags[w] = append(g.bags[w], v)
+
+	g.edges++
+}
+
+// GetAdjacentVertexs returns all adjacent vertexs of v in the graph.
+func (g *Graph) GetAdjacentVertexs(v int) []int {
+	if v < 0 || v >= len(g.bags) {
+		panic(fmt.Errorf(errInvaliVertexNumber, v))
+	}
+
+	return g.bags[v]
+}
diff --git a/graph/graph_test.go b/graph/graph_test.go
new file mode 100644
index 0000000..d79dd4b
--- /dev/null
+++ b/graph/graph_test.go
@@ -0,0 +1,47 @@
+package graph
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/suite"
+)
+
+type GraphSuite struct {
+	suite.Suite
+
+	g *Graph
+}
+
+func (s *GraphSuite) SetupTest() {
+	s.g = New(10)
+}
+
+func (s GraphSuite) TestNew() {
+	s.Equal(10, len(s.g.bags))
+}
+
+func (s GraphSuite) TestVertexs() {
+	s.Equal(10, s.g.Vertexs())
+}
+
+func (s GraphSuite) TestEdges() {
+	s.Equal(0, s.g.Edges())
+	s.g.addEdge(0, 1)
+	s.Equal(1, s.g.Edges())
+}
+
+func (s GraphSuite) TestEdgesFailed() {
+	s.Panics(func() { s.g.addEdge(11, 1) })
+	s.Panics(func() { s.g.addEdge(1, 11) })
+}
+
+func (s GraphSuite) TestGetAdjacentVertexs() {
+	s.g.addEdge(0, 1)
+	s.g.addEdge(0, 2)
+
+	s.Equal([]int{1, 2}, s.g.GetAdjacentVertexs(0))
+}
+
+func TestGraph(t *testing.T) {
+	suite.Run(t, new(GraphSuite))
+}