graph

Author: xiaomeng79

algorithms/graphs/README.md

@@ -0,0 +1,9 @@
+## 图算法
+
+### 搜索
+
+#### 深度优先DFS(Depth First Search)
+
+思想:假设所有顶点均未被访问，从一个顶点V出发，依次访问它的各个邻接点，直到图中所有和V相通的点都被访问到，若还有未访问的顶点，重复以上过程
+
+#### 广度优先BFS(Breadth First Search)

algorithms/graphs/bfs/bfs.go

@@ -0,0 +1 @@
+package bfs

algorithms/graphs/bfs/bfs_test.go

@@ -0,0 +1 @@
+package bfs

algorithms/graphs/dfs/dfs.go

@@ -0,0 +1,48 @@
+package dfs
+
+import (
+	"github.com/xiaomeng79/go-algorithm/data-structures/graph"
+	"github.com/xiaomeng79/go-algorithm/data-structures/stack"
+)
+
+//无向图的深度搜索
+
+func UndirectedDfs(g *graph.UnGraph, v graph.VertexId, fn func(graph.VertexId)) {
+	s := stack.New() //初始化一个栈
+	s.Push(int(v))
+	visited := make(map[graph.VertexId]bool) //记录是否访问过
+
+	for s.Len() > 0 { //只要栈里面有，就一直
+		v, _ := s.Pop()
+		_v := graph.VertexId(v)
+		if _, ok := visited[_v]; !ok {
+			visited[_v] = true
+			fn(_v)
+			//将此结点的邻接点压栈
+			neighbours := g.GetNeighbours(_v).VerticesIter()
+			for neighbour := range neighbours {
+				s.Push(int(neighbour))
+			}
+		}
+	}
+}
+
+//有向图的深度搜索
+func DirectedDfs(g *graph.DirGraph, v graph.VertexId, fn func(graph.VertexId)) {
+	s := stack.New()
+	s.Push(int(v))
+	visited := make(map[graph.VertexId]bool)
+
+	for s.Len() > 0 {
+		v, _ := s.Pop()
+		_v := graph.VertexId(v)
+		if _, ok := visited[_v]; !ok {
+			visited[_v] = true
+			fn(_v)
+			neighbours := g.GetSuccessors(_v).VerticesIter()
+			for neighbour := range neighbours {
+				s.Push(int(neighbour))
+			}
+		}
+	}
+}

algorithms/graphs/dfs/dfs_test.go

@@ -0,0 +1,47 @@
+package dfs
+
+import (
+	"github.com/stretchr/testify/assert"
+	"github.com/xiaomeng79/go-algorithm/data-structures/graph"
+	"testing"
+)
+
+func TestUndirectedDfs(t *testing.T) {
+	//建立一个无向图
+	h := graph.NewUndirected()
+
+	//增加顶点，
+	for i:=0; i<10; i++ {
+		h.AddVertex(graph.VertexId(i))
+	}
+	//增加边
+	for i:=0;i<9;i++ {
+		h.AddEdge(graph.VertexId(i),graph.VertexId(i+1),1)
+	}
+	counter := 0
+	UndirectedDfs(h,graph.VertexId(4), func(id graph.VertexId) {
+		counter += int(id)
+	})
+	assert.Equal(t,45,counter)
+}
+
+func TestDirectedDfs(t *testing.T) {
+	//建立一个有向图
+	h := graph.NewDirected()
+
+	for i := 0; i < 10; i++ {
+		v := graph.VertexId(i)
+		h.AddVertex(v)
+	}
+
+	for i := 0; i < 9; i++ {
+		h.AddEdge(graph.VertexId(i), graph.VertexId(i+1), 1)
+	}
+
+	counter := 0
+	DirectedDfs(h, graph.VertexId(3), func(v graph.VertexId) {
+		counter += int(v)
+	})
+
+	assert.Equal(t,42,counter)
+}

sort/README.md renamed to algorithms/sort/README.md

@@ -2,8 +2,8 @@ package bubble
 
 import (
 	"github.com/stretchr/testify/assert"
-	"github.com/xiaomeng79/go-algorithm/sort/testdata"
-	"github.com/xiaomeng79/go-algorithm/sort/utils"
+	"github.com/xiaomeng79/go-algorithm/algorithms/sort/testdata"
+	"github.com/xiaomeng79/go-algorithm/algorithms/sort/utils"
 	"testing"
 )
 

sort/bubble/bubble.go renamed to algorithms/sort/bubble/bubble.go

@@ -2,8 +2,8 @@ package insertion
 
 import (
 	"github.com/stretchr/testify/assert"
-	"github.com/xiaomeng79/go-algorithm/sort/testdata"
-	"github.com/xiaomeng79/go-algorithm/sort/utils"
+	"github.com/xiaomeng79/go-algorithm/algorithms/sort/testdata"
+	"github.com/xiaomeng79/go-algorithm/algorithms/sort/utils"
 	"testing"
 )